Some ideas:

Foil Protection:
#1 Polyurethane, the stuff used for wood and floors
#2 Silkscreen acrylic ink
#3 UTEE, "Ultra Tough Embossing Enamel" craft embossing powder(think it's the same stuff as powder coat paint), uses a clear "ink" glue to make powder stick and use heat gun to melt shiny.
#4 buy a CD/DVD lable thing at Staples or Office Max
#5 buy quality stuff to save/copy your most important data

Scratched plastic:
#1 see #1 above, some scratches might need light sanding?
#2 Iron or heat gun scratches away?
#3 Try clear UTEE?

Some type of spinning should probably be used to give the disc a thin layer that dries fast. And being in a dust free environment couldn't hurt.

Might want to try this on throw away AOL discs. On second thought, maybe not, you don't want to play around with AOL discs when data installing is involved!

--ED