Marvel Mystery
Oil. I may start using it myself.
27 years ago, we poured that down spark plug holes on sister's V12 E type. Down carbs and in gas. Engine is not locked up.
I did some research on MMO and it is largely laquer thinners and LARD. If it works or not, it won't clog my arteries.
It is not the scam Slick 50 was.