What is the best way to remove desiccant from a broken Dryer that ended up in my R12 system?

they make do it yourself flush kits, basically alcohol in an aerosol can. the best way is to bring it to a shop, (yea i have a shop) (and 9 grand wagoneers) and the professional equipment will do a much better job of flushing that out, plus you need to take the system apart in many sections, you flush the condenser out all by it self so that means taking all the lines out, then you flush the lines out, and then flush out the evaporator core, you cannot flush out the system correctly by undoing one hose and trying to flush it all out through till it comes out the other end of the hose on the opposite side, install a new dryer, oil and freon and you should be fine. And to answer your other questions i seen about bb in the sight glass, when filling up with the freon, compressor running, and watching the pressure gauges, you fill the system up until there are basically no bubbles in the sight glass. The sight glass was put there for that exact purpose, back in the day they didn't know any better and check by weight and pressure like they do know with r134a. HOWEVER, if you refill with the r134 freon (which does work just as good if done correctly) you dont use the sight glass method. You only add 80% of total volume, originally is 36oz of freon so you just add 28oz of 134 if you go that route. Also, these old compressors have there own self lubricating oil unlike other compressors so always make sure the check oil in the a/c compressor itself. Good luck to you!!