When doing projects (messy) use a dollar store shower curtain as a cover for "where ever" the project is being done.
I have used this many times. It even is handy when spray painting objects.
As for "clean" children, usa (again) dolar store pillow cases with head and arm holes cut in them so they fit on the children.
I have 4 "babies" and 3 grandchildren so far and these tips work. Especially on your stress levels!

Clovia