You can check for electrolysis by sticking one voltmeter probe in your open radiator cap and the other to ground. Should have 0.00.
small update w/ setback: I'm not too swift with a voltmeter, but I was getting fluctuating readings around .2 and saw a high of .3 at one point. I figured I could at least clean the terminals and cables so I pulled the battery and used baking soda and water. The positive cable was really nasty and I just kinda dunked it in a cup of solution, brushed and rinsed with clear water as best I could. Tried to catch overflow with paper towels.
Put everything back...argh, car won't start. Just clicks. Test battery; 12.6 volts. Kicking self, figure I got something wet. Dried what I could, let sit. About 4-5 hours later, it started. Drove a little rough, like idling low. Pull into garage, turn off, try restart. No go, argh again. Actually no click even. Not even getting a dome light. Battery still 12+ volts. Is there still something wet or did I kill something?
Hmmm...just a thought, but I didn't try pulling battery and drying under that...man, this is not my forte!