My estimate would be around 500ml or grams he said according to technican...
But then this big vented building so it's not like 100% of it would be cooking off
I think the discussion so far leads us towards a negligible amount remaining unvaporized, a negligible amount of that to react with heat, and be converted to HF, and a negligabil amount of that to remain.
Also, although HF is the nastiest flesh-eating bone dissolving chemical we can basically think of, its a poor hydrogen donor, so not a strong metal-eating acid. Of which there is a negligible amount. On a massive amount of steel.
I'm planning to wash engine with some water I guess that's safe from chemical residue point ... ?
Washing engines was trendy years ago, but its generally considered to be a bad idea. Negligible benefit to de-greasing the engine, risky to damage electrical components, and an ecological burden. From engine grease, and you know, the contaminant you're worried about, now in a puddle, on a surface you now have to clean up.
Like I said, negligible amounts here, but you assume the surface is possibly much more than negligible contaminated. OK, I'll bite. Oh, what to do, what to do -- your plan is, to spread it everywhere out of your control. Why's that better?