Yup, simple green and tooth brush is what I do, but I also rinse off with water when done. I've had a bunch of people say they never or almost never, and that it didn't ocur to them that it could be a problem
Thanks again guys. I ended up using a brake cleaner, pick, a wire brush, and some Q-tips. It took awhile, but they came out pretty good. I took a quick test-ride this morning. It feels like I need to bleed the lines again, but my "ratchety brake" problem is solved. Sweet! It was actually pretty easy. The hardest part was getting the pistons out. I think the trick is to push them out as far as possible with the lever before you take the caliper off the line. I used a clutch holding tool wrapped in a cut-up inner tube to hold them and pull them out.
Next time just use a low pressure air blower with a rubber tip. Press the tip into the banjo hole, use your fingers or a pad to be sure you don't blow just one out and apply pressure. They will smoothly slide to nearly out and you can pluck them by hand for the last few mm.
All good advice, couldn't have said it better myself. If there is one part of a racing motorcycle where you absolutely do not cut corners or worry about saving money, it is the front brakes.