Cleaning the valve body is almost free. The cost is your time, a trans filter and fluid. It might take you the better part of a day to remove it, clean it and reinstall it. When cleaning it, be comfortable, clean and take your time. You probably already watched my YouTube video on this but if not, here it is:

https://www.youtube.com/watch?v=h9thWDLR5yo

__________________
1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge