Used it for years. Used to be the "standard" patch lube. It stiffens up a bit in cold weather, but the real drawback is hot weather. Almost have to put it in a bottle, since it will run right out of an altoids tin. It did the job in keeping fouling soft. As far as contamination of the powder charge goes, it was in my opinion no better or worse than any other lubes. Homemade felt wads cut from weather stripping with a piece of appropriate sized sharpend copper tubing make powder contamination a moot point. I still use it on occassion, but prefer a more universal, all weather patch lube like Moose Snot or WonderLube.