Every summer, right about the time the gravel lane dries out and I start pulling my sandals down from the hall closet, I’m reminded that pretty straps and sensible feet don’t always get along. I’ve had those angry red rub marks across the heel, that stinging raw patch on the back of the foot, and the sort of blister that makes you walk sideways through the kitchen just to avoid touching the floor. After decades of cooking on my feet, working in the garden, and learning the hard way which shoes behave and which ones turn mean by supper, I’ve come to rely on one simple trick more than any other.
That trick is plain petroleum jelly, rubbed in the right places before you put your sandals on. It is inexpensive, easy to keep in a handbag, and far more effective than folks often expect. Below, I’ll walk you through exactly how I use it, where to apply it, when it works best, when it is not enough on its own, and how to help blisters and shoe rub marks heal once the damage is already done.
1. The 1 trick: use a thin layer of petroleum jelly
The whole idea is simple: reduce friction before it starts. Most heel blisters and red sandal rub marks happen because skin keeps dragging against a strap or the back edge of a shoe, sometimes for 500 to 5,000 little steps in a single afternoon. Petroleum jelly creates a slick barrier so the strap glides more easily instead of scraping the skin raw.
I use about a pea-sized amount for each foot if I’m only treating the heel, or up to a dime-sized amount if I’m covering several contact points. You do not need a thick gob. Too much can make the foot slide around in the sandal, which creates a different problem. Think “light shine,” not “greasy coating.”
2. Where to rub it for strappy sandal problems
Focus on the exact spots where the sandal touches and rubs. For most women, that means the back of the heel, the sides of the heel bone, the Achilles area, and any place a narrow strap crosses the top or side of the foot. If the sandal has a toe post, such as a thong-style sandal, I also put a tiny bit between the big toe and second toe.
When I’m testing a new pair, I put the sandals on for 1 minute, stand up, and feel for pressure points. Then I take them off and apply the jelly exactly there. If a strap edge feels sharp near the ankle, that’s the spot to treat. If the back rim of the sandal sits 1 inch above the sole and catches the heel every step, coat that part of your skin before walking out the door.
3. How much to use without making your feet slippery
This is where many people overdo it. Start with about 1/8 teaspoon total per foot. Rub it in with two fingers for 10 to 15 seconds until you can still feel it, but it is no longer sitting in a thick layer. If your skin still looks heavily coated, blot lightly with a tissue.
For leather sandals with firm straps, I sometimes do a second whisper-thin pass just on the most troublesome edge. For soft fabric sandals, one pass is usually enough. If you are going to be walking more than 30 minutes, carry a small travel jar so you can reapply once if needed.
4. The best time to apply it
Apply petroleum jelly 2 to 5 minutes before putting your sandals on. That gives you enough time to rub it in evenly without forgetting where you put the cap. I like to do it after drying my feet well, especially after a shower, because water left on the skin can soften the surface too much and make it easier to chafe.
If it is a hot day above 85 degrees Fahrenheit, or you know you will be outside for 2 hours or more, check your feet midway through the day. Heat, sweat, and dust can wear down the barrier faster than you’d think. In July, after church potlucks or county fair walking, I nearly always reapply once.
5. Why this works better than waiting for pain to start
Once a blister starts forming, the upper layer of skin has already been injured. At that point, every step can enlarge the damaged area. Prevention matters more than treatment. Petroleum jelly helps by lowering the friction coefficient between skin and shoe, which is simply a plainspoken way of saying it reduces the scraping motion that causes heat and irritation.
I learned this years ago after wearing a pair of narrow tan sandals to a family reunion. I thought I’d “break them in” by just toughing it out. By the time the fried chicken was on the table, both heels were burning. Since then, I treat friction before I leave home, same as I’d oil a squeaky hinge before it starts shrieking.
6. When petroleum jelly is enough, and when you need more protection
If your sandal rubs only mildly and you’ll be walking short distances, petroleum jelly alone is often enough. Think errands, lunch with a friend, or an evening on the porch. But if the shoe is stiff, the strap edge is rough, or you already have a tender spot, use a second line of defense.
In those cases, I pair the jelly with a blister bandage, moleskin, or a thin gel heel sleeve. A hydrocolloid blister bandage can stay on for 2 to 5 days, depending on the brand and how much moisture the area sees. If I’m going to a wedding, an outdoor market, or anywhere I expect to walk over 1 mile, I do not rely on wishful thinking. I use both barrier and padding.
7. What to do if the skin is already raw
Do not rub petroleum jelly onto open, weeping skin and then slide right back into the same irritating shoe for a long outing. If the area is already broken, clean it first with mild soap and lukewarm water, pat it dry, and cover it with a proper bandage. If a blister is intact, try to leave it unpopped. That roof of skin is your body’s natural dressing.
For a raw heel that is red but not open, a very small amount of petroleum jelly can help protect it from drying and cracking, but you still need to stop the friction source. Wear a different shoe for at least 24 to 72 hours if you can. If the area is hot, swollen, draining pus, or getting more painful instead of less, that is time to call a medical professional.
8. How to calm red shoe rub marks fast
For plain red friction marks without broken skin, I start by getting the shoes off as soon as I’m home. Then I wash the area gently and use a cool compress for 5 to 10 minutes. After that, a small layer of petroleum jelly helps lock in moisture and reduce further irritation from socks, sheets, or house slippers.
If the skin feels especially warm or puffy, elevate your feet for 15 to 20 minutes. It sounds simple, but after a long day on your feet, that little rest can make a big difference. In my kitchen, I’ve sat many an evening with my heels propped on a folded quilt, grateful for the wisdom of stopping while I was ahead.
9. Sandal materials that cause the worst friction
In my experience, the biggest culprits are stiff faux leather, unlined leather edges, plastic straps, and decorative seams that sit right where the foot bends. A strap can look soft in the store and still have a cut edge that acts like sandpaper after 20 minutes of walking.
Pay attention to strap width too. A skinny 1/4-inch strap concentrates pressure in a smaller area than a broad 1-inch strap. The narrower the contact point, the more likely it is to dig in and rub. If you have tender skin or a history of blisters, soft suede linings, padded straps, and adjustable buckles are worth every extra dollar.
10. How to break in sandals without hurting yourself
I never recommend an all-day first wear. Start with 20 to 30 minutes at home on day one. On day two, go 45 to 60 minutes. On day three, if all is well, try a short outing. This gives the shoe time to flex and your foot time to tell you the truth.
If a leather strap is stiff, you can gently bend it back and forth with your hands 10 to 15 times before wearing. Some folks also use a leather conditioner made for footwear, but use it sparingly and follow the product directions. If the sandal still rubs in the same spot after 3 wears, do not keep forcing the matter. Bad fit does not usually improve with stubbornness.
11. The foot care routine that makes blisters less likely
Healthy skin handles friction better than neglected skin. I keep my heels smooth by using a foot file 1 to 2 times per week after bathing, never aggressively, just enough to reduce rough edges and thick callus. Then I moisturize at night. Thick, cracked skin can catch on straps, while overly soggy skin can shear more easily, so the goal is balanced skin, not baby-soft slipperiness.
Toenails matter too. If nails are too long, the foot can shift awkwardly in the sandal and create extra rubbing at the heel. Trim nails straight across every few weeks and file rough corners. It’s not glamorous advice, but practical habits save more pain than fancy packaging ever will.
12. Smart extras to keep in your bag
If sandals are part of your summer life, make yourself a little rescue kit. Mine usually includes a 0.5-ounce travel jar of petroleum jelly, 2 hydrocolloid blister bandages, 2 regular adhesive bandages, a small alcohol-free cleansing wipe, and a folded piece of moleskin about 3 by 3 inches. The whole thing fits in a coin purse.
Add a pair of thin no-show liner socks if you’re really cautious and don’t mind slipping them on for the drive home. I’ve also tucked a pair of soft flats in the car more than once. At my age, I’ve learned that preparedness is not fussiness. It’s peace.
13. Mistakes that make sandal blisters worse
The first mistake is ignoring the “hot spot.” If you feel burning, stop and check. A hot spot is often the 10-minute warning before a blister forms. The second mistake is putting lotion on the whole foot right before wearing sandals. Many lotions are not slick enough to reduce friction for long, and some make feet damp rather than protected.
Another common mistake is covering raw skin with a basic bandage and then putting on the same rubbing shoe without changing anything else. If the strap is still scraping, the bandage may simply roll up or peel off. You have to address both the skin and the shoe.
14. Who should be extra careful with any foot irritation
If you have diabetes, poor circulation, neuropathy, or a condition that affects healing, even a small blister deserves serious attention. What looks like a minor rub mark can become a larger wound if feeling is reduced or blood flow is limited. In that case, do not experiment too long at home.
Likewise, if the blister is larger than about 1 inch across, very painful, filled with cloudy fluid, or surrounded by spreading redness, seek medical care. Home tricks are for mild friction prevention and simple irritations, not infections or significant skin injury.
15. My plainspoken summer rule for happy feet
These days, I don’t wait for a shoe to prove itself the hard way. If a sandal has even one suspicious strap, I smooth on a little petroleum jelly before I head out, especially on the back of the heel and any place that has rubbed me before. It takes less than 1 minute, costs pennies per use, and has saved me from a world of limping.
There’s no magic in it, just a sensible barrier that cuts down friction and gives your skin a fighting chance. And in my book, those are often the best remedies of all: simple, affordable, and dependable enough to pass from one summer to the next.