IF it's the same stuff I used several years ago on some seized-up old relics it's simply fantastic. When trying it on some more modern items I found it did remove blue/blackening finishes, but seemed to hit the active rusty spots first so that if I was careful I could get a fair bit of rust out before risking much finish. Haven't used it for years, but then again, I haven't acquired anything that rusty in years either. My suggestion is to decide for yourself; if there's enough rust for you to consider using this stuff, it's safest to accept before you start that you will likely be refinishing the item afterwards.