Classic/Antique Car Repair: Powerglide Transmission, 58 impala, torque converter

Question
I am changing the transmission fluid in my "58" Impala with the cast iron powerglide. I drained the transmission and flushed the cooler lines. My question is can the torque converter be drained? It appears there is no way to do this and also I understand there is a screen inside the case. You would have to take the transmission apart to clean it.

Answer
Back in the day there were those mechanics that drilled a hole in the converter case, and threaded the hole for a small pipe plug. The trick is to coat the drill bit with grease to hold the drilling chips to prevent them from entering the converter. Is it a recommended procedure? Not as far as I am concerned if the fluid has been changed in the transmission and the lines flushed.
Brad