I bought a used G-Shock MTG910 off ebay about a year ago that cleaned up pretty well. There were some scuffs on the band that couldn't be cleaned off (the black paint got scratched). I found out that it takes the same style band as my resin GW500A and swapped it with no problem. That band is a lot more durable and almost looks as good as the black metal band. Are there other G-Shock watches that use the same style band? I may eventually go with a black leather strap if I could find one.
The bands on these 2 watches were held on by screws that kept the band on the rubber/resin part of the MTG910 watch and the GW500A. I loosened the screws with a screwdriver block and a small watch screwdriver. Once the screws are out just pry the band away from the watch with the round part of the screwdriver on the underside of the watch until it pops off the rubber (mud may have dried in there like concrete...be gentle to break it without breaking the plastic...maybe warm water would loosen it if it's stuck). Push the other band on and re-screw. No spring bars involved!