I have been off the system for a few days so my contribution to the
"Matting" may be old hat. but.......I presume you all mean "mounting"
the children's work for display?
I work one day per week as a hospital play specialist
( US term "Child Life Worker").
I use my Art education skills to encourage children to mentally
escape from their surroundings. I usually mount at least one piece of
each child's work on card and either display it on the wall or give
it to the parent to take home.
By presenting the child's work in this manner the parent sees that the
picture/painting has some value and perhaps enables them to
understand that "Child Art' is an important aspect of expression. It
also has the effect of reducing the "Colouring Book" dependancy