Any hardware store alternatives?
Valve lapping compound
toothpaste in a pinch
I know it's not the hardware store....but my LBS has a box of samples in the shop. They were freebies to them, so they gave me 2. Try to ask around.
I'm pretty sure it is a synthetic grease with lapping compound added.
This stuff Lapping Accessories - Lee Valley Tools
Mavic contest slideout