For conserving energy and insulating every crack and crevice of your home, expanding foam can be a marvel, but the nature of expanding foam is to expand and adhere to whatever it touches. When it's where it's supposed to be, that's fantastic, but when foam insulation expands further than intended and gets onto objects beyond its application, then that's a sticky wicket for the DIYer.
The best way to remove expanding foam is to avoid applying too much. It can expand up to 300 times its volume, so apply a test bead on some scrap wood or elsewhere so you know how much pressure to apply when doing your project.
Know Your Foam Products
When working with expanding foam, it's recommended to use a mask, goggles, and gloves. Depending on the type of foam and how pressurized it is, it will expand anywhere from 20 to 300 times its volume as a liquid, making it easy to underestimate just how much you've applied. If it overexpands, it can get on skin, clothes, and many other surfaces. Depending on where it is, you may be better off letting the foam cure because it's easy to cut excess foam down to size. For metal, glass, and stone, scraping off foam is a cinch.
Video of the Day
Before you start, check your product manufacturer's suggestions, including on its website, because it may have great product-specific removal advice that makes all the difference for you.
Removing Expanding Foam From Skin
Even on skin, foam hardens and becomes unremovable, so don't dally. You should move quickly but don't panic. If it hardens, it won't harm you; you'll just need to let it flake off at its own pace, which could take a week or so. While many sources suggest using acetone to remove expanding foam, it only works for select products and often isn't successful. Instead, petroleum jelly is the recommended way to proceed, so have that ready to go.
The most important thing to remember is to always use a dry cloth because a wet cloth will make any remaining residue cure onto your skin or any other surface right away.
The Petroleum Jelly Solution
Now that you're ready to remove expanding foam, wipe off the product with a clean, dry cloth. Immediately smear a generous coat of petroleum jelly on your affected skin and wrap it in plastic, such as a shopping bag, cling film, or plastic gloves. Wait for one hour, and your skin's natural oils should release and help lift the foam. When you remove the plastic, the remaining residue should peel off. If not, repeat this step one more time for any significant remaining foam.
After you've removed most of the product with the petroleum jelly method, use a pumice stone to scour whatever is left. It may not remove it all, in which case you'll need to wait a few days until it flakes off. Remember that it's not harmful, so don't worry if this is your result.
After you've scoured off what you can, wash with soap and water. Moisturize with more petroleum jelly if you'd like.
Removing Wet Foam From Fabrics
This process begins much the same as removing the product from skin. The first step is always wiping off the excess with a dry rag. Next, you'll need a rag with acetone on it to dab off any remaining residue. Repeat as needed until the product has dried or hardened.
If foam has hardened on fabric, it will be impossible to remove it all if any. Some DIYers suggest scraping off this residue, but doing so can easily damage your item, and it isn't advised.
Removing Cured Foam
If your expanding foam sealant has bulged out beyond the surfaces you meant to seal, don't try to clean it up while it's still wet. Instead, allow it to cure and then cut off the excess with a knife. A utility blade should work, but serrated will do in a pinch and might be more effective for more voluminous removals.
If you've applied expanding foam around the front door or other spots where it's visible on wood, once you've cut back the excess, you may need to sand down the remaining residue. Use a fine-grit wet-dry sandpaper, like 200 or 220 grit. Some varnish or paint touchup may be required when you're finished.
Avoid using solvents or other harsh chemicals to remove any foam residue from wood, plastic, or varnish, as solvents will not only remove the foam but also the finish or coating beneath it.