When you want to open clean out and you are afraid the pipe is full. Drill a small hole in the clean out plug so you can drain off the liquids before opening the clean out.
JerryDM and JoeD! You two are terrible. Lol. Well I did the manly thing. Rented a snake and went 100ft. Found three blockages. No poopy mess came out the stack because the blockage was below floor level.