Make sure your reciprocating saw has a metal cutting blade before you turn it on otherwise you re in for a difficult.
Drain clean out cap stuck.
If all your efforts fail you may have to cut out the fitting and install a new one.
Use a pipe wrench to loosen the cap on your main line drain pipe before you open it entirely.
Https amzn to 354hhrh plumber s pipe wrench.
I let the water drain out then i cut out the nut using a metal cut off wheel rotozip.
Remove the cleanout plug with finesse and force photo 1.
Dousing the plug several times with penetrating catalyst lubricant often also called a rust breaker is another way to.
Heat the cleanout plug and fitting clean away any.
Open the cap and let the buildup drain out quickly open the cap and step out of the way.
After this i used the cut off wheel to slice away portions of the cap until i could get near the inner.