I clean my Mosin at home after I have finished firing. I have used two methods, one is a patch with WWII bore cleaner of which I have a can, Or dis-assembled I pour hot soapy water down the barrel from the chamber end. Either method run patches until they come out clean and then an oily patch for storing. The bore should be free of that oil before firing again, so a dry patch before firing. Lots of trouble ? No, but letting a rifle bore rust and corrode is a sin !