White encrusted residue eh?
I know you love your bike, but there are standards to uphold...
Get the battery out asap though if you possibly can, there's a lot of acid in there. Only takes a couple of minutes as you know. And lots of water if it does turn out it's leaked or split. I've got a spare battery somewhere, it's old and rubbish but it'll do as a stunt double if you want to test the charging without risking a new battery?