Hi,
Problem is that torque wrenches don't discriminate between dry and greased.
Suggest the bolt is not that tight if you use a torque wrench / difficult to operate if the part is also free to move held with other hand.
Probably a good idea to examine the BB taper for deposits and damage, I normally wipe the taper then take a look and use your fingers (Clean hands) on the taper for nasty's.
Clean out the thread in BB of mud etc, rag stuffed in should be clean after.
Clean out the socket in the crank.
Clean all of the bolt, it should run free in the mating thread with fingers, replace as necessary.
On BB bolts the shoulder sees most of the friction whilst torqueing.
Place the crank arm on the taper and hit it with the palm of hand.
This should be enough that thumping the back of crank with hand till it hurts will just budge it off again.
A minute smidgen of lube on the flats, I probably rub mine with a not so clean rag.
There is probably some residue of lube in the threaded hole.
Torque up bolt ( I normally use a longish wrench, not as longer than the crank arm) I normally use one hand on crank and one on the wrench, bringing hands together across your chest, there will be a point where the thing feels like its stopped moving creaking even as the wrench (hex key) bends and springs slightly.
To recheck the bolt after 50 miles or so apply same force, it may well move slightly or not at all.
I also pack the bolt head if no rubber seal, and rear face of crank with some butyl rubber which has aged some so its rather like plasticine.
Stops the water getting in.
Don't use a wrench longer than crank.
All for an average 11 - 12 stone man.
Keep hands free from grease / muck, I always use nitrile fabric backed gloves and keep rag for wiping hands tucked in to your front / hanging from your pocket, any other use its a rag on the bench.
DONT wipe the mess with the same rag that wipes your hands, you end up with CRAP all over the controls and bars.
Never had a crank come loose, but seen many MTB ones where the shaft protrudes through crank
Good idea to remove cranks periodically, though I would say that unless its stored out side / heavy off road use, they don't seize on.
From experience in motors and lathe tapers on tailstock etc, a bur or lube at all will stop the taper from seating properly, allowing it to turn which wrecks both parts, keys on tapered shafts are for location not driving force.