On my 1966 SJ built Mustang (April '66 Schedule build date) I found "O.K. -9" on the passenger cowl and "120" in grease pencil (I think) under the passenger front of the hood.
The radiator spewed dirty coolant when the car overheated. How may I clean the cowl area without erasing the "O.K.-9" ?
And, is the "120" significant to keep?
Last picture I included because the fuel line clamp has engine paint while the securing piece did not. Also, the bolt for the oil dip stick still has some engine paint left on it.