Hi vint_mow,
Hydrochloric or Sulphuric acid is a topic we really don't want to endorse in any way, shape or form here on ODK, so I'm glad you've highlighted that in Red.
The safest chemical process is definitely Molasses as you mentioned in you post above. Also from a dangerous chemical point of view it's pretty harmless. Basically it's made up from washing powder caustic which isn't going to harm anyone too much. I will say though that the more washing soda you desolve in the water the better it works. No issues with overdosing the small amounts that most "Youtube" videos claim to use.
When I was in the plating game we had very strong caustic based cleaners that you wouldn't want to have on your skin, but washing soda is rather negligible compared to what I used to use on a daily basis.
Using vinegar would be rather costly for the amount you'd have to use to clean a reel or chassis of a mower, thus why Molasses is so cost effective and there's no issues with it going down the drain either. Just don't shove the solids and old paint that remain at the bottom of the bath you make up down there. Let that all dry out and then wrap it up in old newspaper etc. and put it into the landfill bin.
Cheers,
BB.
