easy 1 mate just get ya self some very very fine wire wool and the smallest amount of wd40 mate place wd on the wire wool not on barrels as this may affect the blueing on the barrles and rub gently till the pitting has come off once done this wipe the excess wd 40 off the barrels then get some gun cleaning oil and place on a duster and give the barrels a real good rub down with an oily rag this should then protect the barrels from moisure. every time you have the gun out make sure you clean it properly in side and out and ALWAYS rub down with oil rag hopes this helps mate atb willum.