Interesting... I can't understand risking having WD40 anywhere near a paint project let alone mixing primer or paint in a wd40 cap... I've seen to many disaster cases from Wd40..crazy risk..
What I'found is those little medicine cups they have in the hall in hospitals won't be affected by solvents and have measure marks engraved into them.
I belive in small batches but won't let WD40 or it's cap anywhere near a paint project..
Fisheyes are for fish