Never heard of Playfoam and found this description for those like me
Playfoam is a completely mess free creative play resource that is great for sensory play! This Learning Resources award winning product helps develop fine motor skills for little hands. The non-toxic formula makes this best selling Playfoam great for safe creative play. It doesn't stick to hands, clothes or carpet, just to itself! What's even better is Playfoam never dries out, so children can display their masterpieces rather than having to put it all back in the box!
Probably aimed at the home market but depending on price may be useful to settings.. its the amount needed for a group that may prove costly (Argos and Amazon have the 20 pack a bit cheaper than the manufacturer)