I have a lipgloss I love, but it is very bright, so I don't wear it every day. This means it has lasted me a long, long time. So long, in fact, that the company has stopped making that variety (Dior's Diorific Plastic Shine, in case you were wondering.) The gloss is starting to thicken now, and while it can still be used, it would be easier if it were a bit thinner. Is it possible to thin out a thickened lip gloss? Thanks!
Diluting cosmetics (especially ones used on the lips) is always tricky because you're also diluting the preservative system. I recommend finding a replacement product.