Harden Brass, Old brass shower handle plate does not come off

[bigworm]

This is a pretty old brass two handle shower, the cold water handle is leaking water. I got the handle off but could not get the plate off. It is round and it does not have screws or anything to hold on. What is the brand and how to get it off? Thanks

 

[Marlinman]

It looks to be Harden Brass. The escutcheon will screw off the plastic nipple.

 

[Sponsor]

 

[Dj2]

Use a channel lock adjustable wrench.