Shut Down: Remove Firebrick?

I had posted last year that I spray my stove interior with WD-40 to protect from rust over the humid summer months....and that after a thorough cleaning out and vacuuming the coal ash which would attract moisture from the air and make sulfuric acid to eat away your stove.

The question was asked about smoking on start up and yes, there is some....creates a haze in the air and triggers the smoke alarm. But I start a wood fire early in the season and that first fire burns off all the WD-40 residue. Open the windows to air out the haze and after that it's clean as a whistle burning. I'll burn wood as needed until going to full time coal in mid November.

I find it odd that I never cleaned my Chubby Coal stove in 14 years that I owned it. This stove has a steel outside and cast top and doors. Didn't know about how coal might rot it out. No internet back in the 80's. When I sold it it was just as good as the day I brought it home from the Chubby Dealer. It was in a basement that was humid most of the summer as well. I got a few years out of the chimney pipe at least as well as the baro damper.
Maybe the coal was a good coal with low sulfur? I did buy from lot's of different dealers there over time.
I didn't clean out the Harman as well last season. Too lazy,busy, back problems. The question is will I clean it out next season? Maybe spray inside only with WD now that I know it may get dissolved by acid. The outside looks the same after the summer with no spots or evidence of acid eating away at anything

Cheers