I have basically given up on my 10 year old 7900 which has an apparently unfixable clog in the light magenta channel. But I am going to keep it as a B&W printer as the 3 black link channels are fine. I want to do some color pair cleanings but the printer won't let me because one of the color channels is too low on ink even though I am not trying to clean that channel. Is there a way around this?