I'm using Canon CD Label Print under xp-sp2 with a pixma ip4200 printer. For the past few days, most label print colors come out green except for brown or creamish colors. Black comes out as dark green.

I've gone through all the maintenance operations such as injector cleaning and so forth. I physically checked the cartridges themselves which all contain liquid.

I updated cd Label Print to 1.30.

Maybe the cartridges themselves are clogged up. Should I dip the cartridge nozzles in hot water or something like that?

Your printer uses ink tanks, not "cartridges". The CD print function uses photo print settings, so try printing the same images on photo paper with photo paper settings and see what they look like.

Run the "nozzle check" test on the maintenance tab and report the results. If that turns out alright, then create a page with large bars of cyan, magenta and yellow color, and print that to see if the printer is able to sustain the ink flow. If not, it's the tank itself that's clogged, not the head.

Most color shift problems are due to clogged heads or clogged ink tanks. You failed to mention if you're using Canon inks, so let's assume you are.

If the nozzle check test fails, then you have an issue with the head. Cleaning might fix it, but often it requires removing the head assembly and soaking or forcing cleaner through the ink channels. If the nozzle check shows clearly defined bands of missing color, then a burned out head is likely the problem. Cleaning won't fix that.

Yes, I've had the same problem with greenish prints, it's likely the black that's not coming through and will show errors in the tests. Replacing the ink tanks didn't help and I couldn't get the head to work again even after extensive cleaning attempts and had to replace it.