Vinegar will work like a charm if you have hard water (white calcium deposits) but it looks like some rust. Like someone else said, use some channel locks with light pressure and use a rag on the teeth to prevent it from scratching the chrome. Clean it really well afterwards.
Ben2ek t1_j2erxbi wrote
Reply to Removing Cartridge on Delta Faucet? by SSFx93
Vinegar will work like a charm if you have hard water (white calcium deposits) but it looks like some rust. Like someone else said, use some channel locks with light pressure and use a rag on the teeth to prevent it from scratching the chrome. Clean it really well afterwards.