I changed some dry crusty thermal paste on my ignition amplifier a couple years ago.
Went to the store that bought out Radio Shack. Called The Source. I'm in Canada, so maybe not helpful for your location. But I will say this. Thermal paste was terribly expensive tiny little tube for like 12 bucks and did absolutely nothing to solve my ignition problems. If you're stuck and really can't find any stores in your area, I'd be willing to look for the leftover tiny 0.5 oz tube probably in the rear tool hatch compartment and stick it in the mail for you. Worst damn 12 bucks I ever spent. Helping a fellow brickboarder - priceless.