The correct terms or phrases are Disrespect and/or Piss Poor Polishing. Meld or melt is just a fancy way to cover over the fact that you polished off half the markings, dished out the screw holes, made straight lines waivy, corners soft and wiggly and in all respects,,,,disrespected the weapon with lack of skill. Hell, even Kimber does it from the factory (with regular kimbers being the seconds and melts being the thirds, heck, seems they make no firsts!)
Really, the ones you see melted are the ones that have always been too big for pocket carry. Meld or melt is worse than gun paint...much as I hate paint on good gun steel, I'd rather see a wad o Durakrap laid down than a melt! But then, I can be a bit opinionated.