On a steel-string acoustic guitar, how do you prevent gunk from building up on the strings? Every time I play, the strings, particularly the B and E strings, will literally (okay maybe not literally) slice the skin off my (left-hand) fingers, and in a matter of days the strings (again mostly the B and E strings) will be full of gunk, making the strings not vibrate as much and overall sound quite dull. I know it's not rust because I have rust on my electric guitar strings, and it doesn't come off as easily.
It is quite hard to clean all of it, as a lot, though not most, is on the lower frets, so the only option is to clean it with a rag or something similar. That doesn't manage to get all of it, however, and the strings still sound dull compared to when first put on.
I've tried many strings, from extra-light to medium, same result. Perhaps it's the texture? The only ones I haven't tried are Elixir's and similar coated strings. I play nylon-strung guitar quite frequently and have had none of these problems, though I suppose you would assume so considering it has half the tension.
I'd rather not have to clean the gunk. I know people who don't have this problem, so I would hope there's a solution to prevent this altogether.