How do I remove expanding foam from skin, clothes and surfaces?

Uncured foam wipes off with the right solvent and cured foam does not come off at all — which makes the first ten minutes the whole of the job.

Difficulty: beginner
Time: 20 min
Read: 4 min
Safety: warning

Short answer

While it is still wet, use the manufacturer's foam cleaner or acetone on hard surfaces and a dry wipe followed by soap on skin. Once cured, nothing dissolves it: cut and scrape the bulk off mechanically and abrade or polish the residue. On skin, cured foam has to wear off over several days.

This is one of the few household materials where there is genuinely no chemical answer once it has set. Cured polyurethane foam is chemically inert and mechanically tough, and every solvent marketed as a foam remover works only on the uncured material. That single fact should shape how you set the job up in the first place.

Safety

Uncured foam contains isocyanates and is an irritant and a sensitiser — wear nitrile gloves while cleaning it up, and never use solvent on skin without checking it is suitable. Foam or its cleaner in an eye is a hospital matter: flush with water and get medical help, do not rub. Foam cleaner is flammable and gives off vapour; ventilate and keep it away from flames.

What you'll need

the manufacturer's foam cleaner, or acetone
nitrile gloves and eye protection
kitchen roll and rags
a serrated knife or a sharp scraper
a plastic scraper for delicate surfaces
abrasive paper and, on hard surfaces, a polishing compound

Step by step

Act immediately if it is wet.The whole outcome is decided in the first few minutes. Wet foam wipes off; cured foam does not come off. Keep cleaner and kitchen roll to hand before you start foaming, not after the accident.
On a hard surface, wipe wet foam with foam cleaner or acetone.Dab and lift rather than smearing, changing to clean paper each time. Test acetone somewhere hidden first — it dissolves many plastics and strips paint and varnish on contact.
On skin, wipe it off dry first.Kitchen roll or a dry rag to take off as much as possible, then a solvent-based hand cleaner or a proprietary wipe, then soap and warm water. Do not go to water first, which spreads it and starts curing it.
Accept that cured foam on skin has to wear off.No solvent touches it once cured and picking at it damages the skin. Wash, moisturise and let it come off with the surface skin over several days. This is why gloves are the answer rather than the cleanup.
On cured foam on a hard surface, cut and scrape.A serrated knife to take the bulk down close to the surface, then a sharp scraper held flat, then abrasive paper and, on a hard finished surface, a polish. Work patiently — you are removing a tough plastic from something softer than it is.
On glass and glazed tile, use a razor blade held flat.Cured foam shaves off glass surprisingly cleanly. It will not work on acrylic, painted surfaces or powder-coated metal, all of which scratch.
On fabric and carpet, freeze and cut.Ice or a freezer pack makes cured foam brittle enough to crack off, and a small pair of scissors takes the rest out of the pile. On clothing, it is usually permanent — cut the surface off and accept the mark.
Prevent it next time with tape, sheeting and gloves.Tape both edges of the joint, sheet the floor and the sill, wear gloves and old clothes. The three minutes spent masking is the entire difference between a clean job and a permanent mark.

Tips

Every foam brand sells a cleaner for its own product, and it is much more effective on wet foam than a general solvent. Buy it with the foam rather than after the accident.
The gun cleaner and the surface cleaner are usually the same thing. If you own a foam gun you already have the right solvent to hand.
Do not spray foam cleaner onto a painted or varnished surface without testing. It is aggressive enough to strip both.
Foam on a uPVC frame is difficult because you cannot use a metal blade without marking it. Cut back with a plastic scraper and finish with a fine abrasive and a uPVC polish.
Cured foam on a carpet can sometimes be cut out of the pile with small sharp scissors so precisely that it is invisible. It is worth trying before writing the carpet off.

If it doesn't work

Cured foam on a painted surface

Cause: It bonded to the paint — Fix: Cut and scrape carefully, accept that the paint will come off with it, and fill and repaint. Trying to get it off cleanly usually damages more than repainting would.

Cured foam on a uPVC window frame

Cause: Overspill during frame foaming — Fix: Pare it back with a plastic scraper, then a fine abrasive and a uPVC polish. Do not use acetone, which crazes the plastic permanently.

Foam on skin that has cured

Cause: No gloves — Fix: There is no remover. Wash and moisturise, and let it wear off with the surface skin over several days. Do not pick or abrade it off.

The stain remains after the foam has gone

Cause: Foam stains porous surfaces yellow-brown — Fix: On timber, sand it out. On masonry, it may not come out at all. On fabric, it is usually permanent.

Questions people ask

What dissolves cured expanding foam?

Nothing available domestically. Every foam remover works on uncured foam only. Cured foam has to be cut, scraped and abraded off.

How do I get expanding foam off my hands?

While wet, wipe it off dry, then use a solvent-based hand cleaner and soap. Once cured, it has to wear off over several days — which is exactly why gloves matter.

Will acetone remove expanding foam?

It works on wet foam and does nothing to cured foam. It also dissolves many plastics and strips paint, so test it somewhere hidden first.

Can I get foam out of a carpet?

Freeze it hard, crack the bulk off, and trim the remainder out of the pile with small sharp scissors. Done carefully this can be almost invisible; done in a hurry it takes a divot out of the carpet.