Same situation, but our idiot floor guy (contractor's sub) sealed the foam droplets into the concrete. And no, there's no way to get it up.

There is no solvent for most of the foams once they have cured.

Mechanical removal is about it.

Cut off as much as you can with single edge razor blades, and then use a wire brush (preferably not steel) to try and remove anything that remains.

A steel brush can cause a rust spot to form from moisture in the concrete and the steel the abrades onto the surface of the concrete.

DW-40 worked on my skin... (oops......)

The glob that got on my floor I got up with a razor.

I'm the personal assistant to the owner of an insulation company that uses spray foam. I will ask her and see what she says and get back to you.

I got a reply-you have to sand it off.

Why didn't I think of sanding? Will have to be careful, but should be able to get the stuff off prior to hitting the actual stained concrete. May have to recoat some of the sealant, but its worth a try.

Thanks

"Why didn't I think of sanding?"

This tends to cause damage to a larger area than the spot.

Picking it off is the low damage path.
Cut it off with razor blades as much as possible, then go after any remaining spots.

"Acetone is the solvent used to thin/remove most spray foams, and can be effective even when they have dried. "

Once polyiso foam (the common can stuff) has cured acetone will no longer dissolve it.
It will dissolve the uncured foam.

There is NO solvent for many of the foams once curing has completed. These are on-way chemical reactions. unless you want to go after strong acids and bases.

Another possible solution from a drywall/insulation owner: ammonia and a wire brush. Be sure to use a dust mask.

Before sanding i would suggest using a green scotch brite pad.My husband and I are foam techs.We use the green scotch bright pads on almost anything.it will scratch the finish if you rub too hard but makes a small area to have to refinish.good luck!

Acetone won't touch it but paint remover will work on thin stains.

Hopefully they found somethng. It has been 10 years.

I will try Acetone. But everyone has different ideas. My spray foam is on wood floor.

If it is still there after 13 years, a hammer and chisel.