How to remove retainer nut without scratching the finish

[algal27]

Hello,
Please forgive me ahead of time if I don't use the correct terminology, but does teach me the correct word. I am not a plumber.
I have a very expensive kitchen faucet that drips from the single handle. There is no brand that I can see to look it up that way. I beleiveni need to replace the cartridge but I can't get the retaining nut off. Can someone give me any pointers? Please see pictures.

Thank you
Allison

 

[Geofd]

The bottom right picture, it looks like that piece over the cartridge may thread off

 

[GReynolds929]

Hands, strap wrench, or plastic jaws on your channies. That looks like a Moen, they should send parts for free if you contact them.

 

[algal27]

Update: it's the trim cap that I can't get off and it's a danze faucet. It looks like it needs a4 prong spindle nut wrench. Does that sound right?

 

[GReynolds929]

The trim cap is supposed to unthread clockwise by hand, but they can get stuck tight. You do not want to mess with the brass piece with the four notches in it, that holds the cartridge in, or the brass valve body in.