Best Off-the-Shelf xW-40 or xW-50 Oil....that Cleans?

[userfriendly]

Could be the 38 year old valve seals.
For cleaning up the rings and grooves, Delo or Duron SAE 40 works for me without the snake oil additives.

 

[AdmiralYoda]

Could be the 38 year old valve seals.
For cleaning up the rings and grooves, Delo or Duron SAE 40 works for me without the snake oil additives.

Zero smoke at start up, even after sitting for weeks.