Ballistol is mostly mineral oil. Read the label. Honest. You can buy mineral oil very cheap, here. You can use mineral oil to help preserve the gun finish, to lube patches, to clean the bore and chambers, etc. I have used WD40 but found that once it dried, it congealed into a pretty tough grease. That will dissolve easily with another squirt or spray of WD40, so its not a long term cleaning problem. I use soap and water to clean the BP revolvers, and then give them a good oil. Because I have a spray can of Remoil on hand, I tend to use that, rather than my WD40, which I save in the shot to use on tools. I am going to buy some mineral oil to use as a patch lube to see how that works out in various temperature ranges, and I expect it will become my dominant protective coating in the future. I am also using Young Country Lube 1000, or what is now marketed as Wonderlube, to protect my long guns. The guns are stored inside the house, in a cool closet, but without a lot of humidity issues through the year. Rust has not been a problem.