Found an old receiver remote that the batteries had corroded in. It doesn't work with cleaning and new batteries. Is it

[Dennis S]

I ran across a long-lost remote to a 20+year-old Technics receiver. The batteries were corroded, but not really bad. I cleaned the corrosion with a toothpick and toothbrush and loaded some new batteries, but it doesn't work. I've cleaned behind the negative metal flaps as good as I physically can. Is there some kind of liquid that it can be soaked in safely to clean it? Does the corrosion, which wasn't terribly bad, eat its way into the innards of the remote?