I don't use my Color StyleWriter 2500's that much - more inclined to use my Personal LaserWriter LS and NTR - - - but more often than not I experience a persistant problem with 'clogged nozzels' in my ink tank. I've tried all the common remedies, i.e. zip lock bags when not in use - - - putting spent cartridges in the tank and capping off the good ones etc.
I've come across a fix that might be of interest to others - relative to clogged nozzels.
As I mentioned above, the cleaning solution cartidges I used up had an oder of ether. I went down to the garage and located a half finished jug of dry-gas left over from the winter. I poured some in a poly coffee-can lid. Then I removed the spent color and black ink cartiridges and poured some in each cartridge well. I found a 6-inch piece of clear neoprene 1/4" ID tubing. After about 20 minutes of soaking the ink tank, I place the tubing over the ink-well-inlets and blew them out one by one holding a piece of paper towl at the bottom of the tank to act a blotter.
I reinstalled my good cartridges and ran a few test prints - after about the third pass, I was back into full color and all ink jets seem to be dispensing properly once again.
A little work but it beats paying $40+ for a new Canon BC-21e tank