Battery evaporator thingy

[browntown]

So under the battery tray I find this 20 year old yellow reservoir thingy that has a hose presumably to the battery, but it was long disconnected by PO's.

I pull the thing out and there is an inch of liquid floating around, and like an idiot I hold it up and said liquid dumps all over my legs and foot.

I'm assuming this is water, but on the off chance it's dilluted battery acid I hosed down my leg.

Should I be concerned? I'm paranoid my leg is going to melt soon.

[browntown]

its the "expansion tank" # 11

http://realoem.com/bmw/showparts.do?model=1423&mospid=47322&btnr=61_0675&hg=61&fg=30

[BahnE30]

trust me, you'd know if you had acid on you, it finds cuts you didn't know you had almost instantanious, and after 5-10 minutes it'll eat your skin, so if you've had it on you longer than that and it doesn't burn your good to go...