keyboard keys

I'm restoring a TRS-80 model 1, 16K level II basic, cassette tape version (though I dont have a cassette tape player yet, just lots of tape software). Anyways, every key seems to have keybounce problems. These keys are the kind with a rectangular tube which, when depressed, allows two contacts (one flat and one with about 4 prongs) to come into contact with each other. There is a strange mustard-like substance in each key in various places near the contacts. I'm wondering if this yellow stuff is supposed to be there, ie, is it some sort of conductive rust preventative? Is it supposed to be the color of old mustard, or has it seriously decayed in the past 21+ years? Suggestions on how to properly clean/refurbish this to near-new condition would be appreciated. -Lawrence LeMay