I have a Delta ball-type kitchen faucet. It's the same one for which I
busted the set screw a few nights ago. With that replaced, I'm back to
trying to get the cap off so I can eventually get to the diverter. The
sprayer isn't getting much pressure, and I had just replaced it, so I
expect the diverter is at fault. However, I cannot get the cap off.

I removed the plastic retainer ring with some long-nosed pliers. After
that, I taped up my plumber's wrench and went to town. I can see the
faucet base trying to turn in place; it's more likely I'll rip off the
faucet from the base before I get that cap loosened. Lefty loosy, correct?

I tried spraying in some liquid wrench, but it hasn't seemed to help.
I'm thinking if I follow that up with a lot of vinegar, I might be able
to get away at the mineral deposits that seem to be holding my faucet
together. Just pouring vinegar into the ball with the handle removed
gave me a little more pressure from the sprayer. Is there anything
clever to do, or do I have to replace the faucet?