I have a number of LaserJet 5Si/8000/8100/8150s here in the company I work for.
Now, a problem that seems to spring up quite often (more often than it should, in my opinion) is that the middle of the upper fuser roller gets what seems to be layer upon layer of toner torched onto it. The stuff is unbearable to try to scrape off, and requires about a 6-hour cool down period before I can try to scrape the stuff off, but that knocks a printer out of commission for the better part of a whole work day. And the things are bloody expensive - upwards from $300 a pop. So I only like to replace them when they're absolutely burned out.
My question is, if anyone else has a similar problem, what do you use to clean the roller? I've tried dry towels and scraping with my fingernails, damp towels, and even isopropyl. But nothing seems to loosen this stuff up! Is there a special cleaning fluid for printer parts like this that are good for taking off baked-on toner from an upper fuser roller?