Cleanout help

I "installed" RootX today in a home I have lived in for a short time. I applied pipe dope on the cleanout but had a hardtime tightening it down because it had too much crud on it. It appears it has been frequently removed, probably due to the roots. I am not sure if the compound was not applied thoroughly, or I damaged the thread but a little water dripped out when I flushed the RootX with water from an upstairs bathtub. The pipe is 4".

I plan to first clean off the tons of old pipe joint compound (wire brush?). My question is:

Should I use a new standard plug?

or

Should I switch to a wingnut plug? (Is that permitted for my vertical cleanout?)

I plan on applying the RootX once a year so easy access is worth the money IMO.

Thanks!

I would get a new plug, clean the threads on the fitting, and use teflon tape rather than pipe dope.

A wingnut plug (we call them dollar plugs) will surely leak as the rubber that gets expanded would have to fill the threads as it was tightened down. A wire brush with the handle removed fitted in a drill will give you better results than just hand brushing. Can teflon tape and then pipe dope the cleanout plug before reinstalling, too.

Thanks for the great advice!

I would use a brass c/o plug in that application.