Quote Originally Posted by michaelbsc View Post
Vinegar is dirt cheap where I live, and I imagine it isn't expensive anywhere.

So a couple of bucks for a bottle of vinegar is you don't happen to have it already in the kitchen, and cut it to 1+3 is where I would start. Not sure what concentration would be recommended to clean calcium stains. But 1+3 should be about 1-2% acetic acid for most grocery store brands.
Michael, excellent! I guess I was just a bit concerned about soaking a negative in vinegar! I will certainly give it a try, the negative is worthless to me in its current state. And the thing is, it's such a great image!