I strongly agree on the oily rag but sometimes things get beyond ones control.Well I have had many guns in that condition come to me for restoration but 99% are guns that have been forgotten about and have been in attics etc for over 100years but the gun in question has been left for the excess of 20years to reach that condition is only pure neglect and should never have happened, I am not trying too offend the person but only pointing out how wrong he or she was when a oily rag would have kept the rust at bay .
Feltwad
Before
View attachment 57806
AfterView attachment 57807
Really Nice restoration on that double ! My hats off to you !
Thanks
O.R.