Micarta is linen cloth, canvas, or rags as substrate that has been formed into layers and phenolic resin (I think, from memory) impregnated under pressure. The resins are cured with a curing agent, just like epoxy is a two component mixture...the epoxy "glue" and a curing agent that causes a chemical reaction that sets it up solid.
I'd be very surprised if micarta were breaking down, oxidizing. Maybe if you left it in the sun for ... oh ... months to years. I've had a number of micarta knives for a few years, oldest is maybe 5 years?... but they don't get left laying outside in the sun, they spend 99% of their life indoors, the rest or on my belt, etc.
Is it bead blasted micarta?
If you solvent clean a bead blasted micarta, it'll get a whitish look to it... it's pretty much just super clean, nothing in the pores at that stage.
If you then oil it with anything from your own hand oil to other petroleum type oils, it'll darken significantly. If you don't want to keep it oily... well ...
You might try to wax it. Turtle wax will do no harm, and will seal up the pores, won't come off for a while, and is pretty much non-harmful and not oily. Haven't tried this myself, but you can always quickly strip all the wax off later w/ acetone or MEK w/ zero risk.
Of course Renaissance Wax is what a lot of knife guys us on carbon steel blades during shows, etc. And for storage. Mostly because it's a very refined product, totally white and clear when buffed onto a blade. It's also very expensive, and not worth buying just for a handle.
