Replacement foam for Cartrivision cartridge and tape cleaner?

[Cartrivision]

I have some old recorded Cartrivision cartridges in which the foam adjacent to the 1/2 inch videotape has deteriorated and needs replacement. Does anyone know of a source for some material that I could cut to fit? I am not sure if any special characteristics are needed (anti-static, etc.).

Also, does anyone have any suggestions on what to use to clean the tape with prior to running it through a player? I was thinking of using a soft cloth lightly dampened with alcohol to remove any loose material, to not gum up the heads while attempting to play the tape. I'll have to rig up something to do so and not damage the tape in the process.