I was given wooden frames with foundation. Can I mix a box with some plastic and some wooden with teh foundation.
You probably won't want to mix foundation and plastic inside the same box. Have the bees draw out one box most of the way before adding the next box. Once they are drawn out you can mix and match as much as you want.
The bees are more reluctant to draw plastic, and if you mix inside a box they can make a mess, drawing out the foundation until they hit the plastic. If you don't have a full box of either, then I'd put the wax foundation in the middle and the plastic on the outsides. Move them around as necessary to completely draw them all.