I have moved many of mine from A to B on a hand trolly, and decanted the electrolite from many. When decanting I suspect most, if not all the lead sediment runs around the side of the casing. In any case I have had no problems.
Apropriate safety gear, in particular a full face shield, if they are open vented some tape over the hole so no electrolite can splash out.
If one shorted (in my opinion highly unlikley) it would "melt", without a sourse of ignition any gas would not explode, so no naked flames.
So you are right to be cautious, but with apropriate care it can be done safley.
allan down under