Originally Posted by CaptMidnight
Diesel Fuel leaves a heavy residue and must be removed with a solvent. There are many modern Action Blasters that are of low viscosity an active solvents that dry quickly with zero petroleum residue. They can also be used without stripping the action.
Handgun action shooters such IPSC can run hundreds of rounds. The guns can be flushed in minutes and back in action.
Some agreement here, some not..
Diesel fuel will also "Creep" into areas (when submerged) that other "Blasters" will not get into. Diesel has enough lube qualities not to gum up any action.
After the OP gets this Smith back to working in correct order (By working many dozens of times.) light lube may be added.
This method will work, does not cost much, and does not require a gunsmith..Bill.