tbone, in my view, and limited by my visualization of what your foundation looks like, you may be better off in the long term to install new foundation. The idea of foundation is to provide a template for the shape and spacing of cells, and to go along with the requirements of bee space. If all you have remaining is plastic with no texture for the base of the cells, you are going to be surprised by irregular comb construction. If you have texture, you might get away with adding wax. I have heated water in a tall stock pot, then added wax. Then you can dip the frame in the heated mixture (one end at at time) for a thin, even coating.