Digging up an old one here but...
We do "Full" internal cleanings once a year which gets rid of the rainbow colors and generally foggy/poor image. We also clean filters whenever the warning comes on.
I was coming here to find out if anyone else was doing the same and see if they had any cool tricks... Only takes less than an hour and that saves a LOT of money compared to... finding what you are going to buy to replace it, getting a P.O. setup, receiving it, accounting having to pay for it, pulling down the old, changing out the mount, adjusting the new projector and... oh yeah... and PAYING the $$$ for a new Projector ;)
We can't be the only ones are we?