Old Film flash making my batteries burst

So I have two 540EZ old Film flashes. They work great and all especially for their price, just I can only use Manual mode.

Now, lately for some reason whatever batteries I put in one of them, a couple days later I'll find that the batteries have bursted (weird white and brown liquid flowing out of the top). This isn't the first time it happened either- after swapping them, the next time I find out my flash doesn't turn on I find that the batteries have bursted again.

After they've bursted of course I'll have thrown them out (well, recycle), cleaned the area touched by the battery guts with a little cleasing alcohol, and put new ones in.

I use Duracell batteries.

Anyone have an idea what could be causing this?

EDIT: Now my flash doesn't work regardless of which batteries I use.

1) were they all from the same batch?
2) are you absolutely certain you put them in the right way? Being installed backward might have caused this.

Can't quite remember whether they were from the same batch or not, but I was 100% sure I put them on the right way- flash works no problem right after

Sounds like a short from the first time you had a leak due to leaving old batteries in the device which is completely draining the new batteries. My advice would be to stick a piece of plastic, tape or non conductive material across one side of the contacts or remove the batteries entirely when not in use.

OK, now my flash is dead.. no batteries work

Sounds like there is a short within the flash units themselves.

Time to open it up and clean the corrosion off circuitry with a swab of soda water or alcohol followed by some clean water. If it does not smell burnt chances are it's not totally dead and can be revived. Usually if the corrosion gets real bad it can destroy resistors on the board but it might be the contacts which are shorted.

Since its dead at this point anyway it's worth taking apart but be forewarned flash capacitors hurt like hell if you get zapped. So once you open the device be sure to short the contacts of any capacitors inside with a screwdriver to safely discharge before handling.