DanG wrote:
Don't I remember there being something pretty simple that would
eat the steel bolts and not affect the aluminum? It may have been
alum. ...

Oh, yeah - I remembered nitric acid would dissolve steel, but not
aluminum, and alum does, too. In my case, though, I didn't need to
preserve the aluminum, so drilling out made the most sense. Easy & fast
- I should have just done it in the 1st place.

I've tried the penetrants, the home made Ed's red, electrolysis,
hand impacts, welded on nuts. I guess we all have. It is always
a joy when you get any one of them to work, ...

A joy, indeed - especially satisfying to have avoided making things worse.

It is always satisfying to solve or save or resurrect someone's
old piece of junk. There is always the luxury of saying before
launching in, "it doesn't work now, does it. I guess we can't
hurt it very much. Be aware there are no guarantees."

Ah, "resurrecting" - I love resurrecting.

Just helped a fella get out some bolts on an 85 Subaru PU
catalytic converter. Ended up drilling out the thoroughly
rusted/corroded bolts in the shop. Guessed center pretty well,
the old stuff never let go until I used SAE tap in the metric
holes ( I don't own metric) . He was able to buy new #10's and
reuse the holes.

With any luck, he has skills and/or tools that you don't & will reciprocate.

Bob