If they still work dirty then I would say you're getting off lucky. If the magazines were designed to work dirty you would have bought them that way. The way I see it, if you keep your kit clean and all worn or damaged parts replaced. Then when the firearm fails you can blame the firearm. If you don't maintain your kit and it fails, blame yourself.
The difference between hot lips and steel lips is indeed the steel mouth on the magazines. All of my hot lips mags have #### the bed in less than a year/season of gopher shooting. They're nearly half the price but they fail far more often.
I'm sure some cleaners will damage the magazines. Soapy water works as well. The baked and caked on carbon will require a stiff brush or a dental pick to get off. Always dry your magazines after cleaning.
Misfire,
10,000 rounds in 5 years??? Only 2000rds/year on average. How do you sleep at night! Feed your rifle and feed it alot.
TDC