Today, I cleaned our HP Color LaserJet 2605dn printer. By the way, it is spelled “Color” and not “Colour”, even though it was sold here in the UK!
The printouts from it were getting more and more washed-out and tending towards green.
I found a solution to the problem on FixYa and, in case you have the same printer, I have written a page describing each step of the process to fix the printer. Just be sure its out of warranty as you have to disassemble it!
The results are worth it, though!