lol wow.
I have some servers in my unfinished basement that have been running 24/7 since I got the house, other than short down time during a UPS upgrade/rewiring/relocation a few years back. I'd be scared to see how bad it looks inside of them. Probably not that bad though.
My next goal for my server room is building the air handler unit (which will have hepa filters) and then enclosing the room. Then dust wont be so much an issue.
Occasionally I vacuum the front of the servers to clear the worse of it.