I would take all of the stuff put it in a zip bag and up on your shelf telling child sorry you didn't play with it properly just as any other toy would do. Put pail with coat to go home. When mom comes send child home with pail only. If mom protests tell her sorry she was painting stuff she shouldn't have and I took the messy things away.

What is mom going to do besides demand them back. Mom needs to learn a lesson too. Giving the stuff back lets mom think she got away with it too. If child goes home sad and protests well mom will have learned a lesson and it will be up to her to replace the items. If child protests at daycare tell her that that mom will have to buy you new stuff to use at home. We don't play with those kinds of things at daycare. Next time - and doubt there will be a next time - mom takes item back to the car at drop off - not even leaves it in the cubby as in are not responsible in any way for it or for telling the child they can't have it.