This topic has been covered a few times with removing yellowing of clear, but I've got some other kind of weird stain in clear. I took a bit out using gentle rubbing with a more aggressive compound (Mothers), but ... surely there must be a better/easier/safer way? I'm afraid to dig much deeper into the clear.

Paint truly is my weak spot on bikes. I can deal with metal, rusty bits, mechanics, but I can't get the wicked luster out of paint I see other people doing. It's pretty frustrating. Stuff like what you see in the red box here kills me (note: that's clay in the lug seam, not rust)