Already do. Granted it's nowhere near how much I used to do when I was back in school but I still do an odd clean or redraw for certain series.
I originally started to give back to the community but I also learnt a lot more about Photoshop thanks to the years of cleaning and redrawing. Now I just do it because I've been working on Freezing
for years and I will see this damn manga out until it finally finishes (please Im Dal Young have mercy and end this clusterfuck of a series)
I'll probably retire after that. I don't really read manga anymore. Either that or I'll switch to a group that specifically cleans yuri series/doujins. Can never have too much yuri in the world.