You've a few options really, Automotive paint stripper and patience if you want to DIY it or you could take it somewhere like Armourtex who will heat strip the paint off, other places who do acid dipping or media blasting are also options
I had a frame media blasted by a place back home, it depends what type of "raw" finish you want and whether you want a clear coat over the top or not to protect it.
You've a few options really, Automotive paint stripper and patience if you want to DIY it or you could take it somewhere like Armourtex who will heat strip the paint off, other places who do acid dipping or media blasting are also options
I had a frame media blasted by a place back home, it depends what type of "raw" finish you want and whether you want a clear coat over the top or not to protect it.