I've been using M Graham & Co. Walnut oil to clean my brushes.
http://www.mgraham.com/html/nontoxicpainting.htm]www.mgraham.com
Step #1 Remove as much paint as possible using a dry rag (paper towel)
Step #2 Dip into brush washing container and wipe again
Step #3 Repeat step #2 until most color residue is gone
Step #4 Squiggle brush against screen at bottom and wipe off (repeat until brush is clean)
Step #5 Repeat step #4 in
second brush washing container until brush is clean
Step #6 Wash with soap and water until you have perfectly clean suds. I use Murphy's Oil Soap.
Step #7 Reshape brush and lay flat to dry
Here is the brush washer I use. Sold by Jerry's Artarama.
http://www.jerrysartarama.com/art-su.../0053189000000
Your brushes will love you!