Cleaning Enameled and "glazed" Cast Iron

Picked up a very old French (Cousances) cast iron pan with a glossy enameled exterior and a non-enameled but "glazed" bottom. Would like to remove carbon crud from the bottom but have read cautions about both lye and electrolysis effects on enameled cast iron. (And I'm not sure what glazed cast iron even means). Any thoughts on how to approach cleaning?

A clear glaze was applied to non-enameled surfaces by makers like Cousances and Le Creuset. It helps prevent rusting of those areas. Rims of pots and ridges of lids were the most likely to suffer damage if enameled like the rest, and at various times some chose to do the same for entire pan bottoms.

As to cleaning yours, it's tricky to remove carbon without hurting the enamel. Some ideas here: http://www.castironcollector.com/forum/showthread.php?t=7505

Thanks, Doug, I'll give it a look.

I picked up a Lodge enameled skillet and it had been used by someone from the no soap club and had a crud layer cooked on it. I tried to scrub it off but it was cooked on baked on and wouldn’t budge. I finally said to myself. I don’t care if it’s a little dull looking after the lye bath at least it will be clean. I cleaned it in the lye bath and it looks so much better and I don’t have a new one to compare it to but it is shiny and clean!

Here's how it turned out. Simmered the bottom of the pan overnight on the stove in a large stainless pan with water, couple squirts of Dawn and 6 or 8 squirts of easy off cleaner-degreaser (has some lye in it but not the yellow cap oven cleaner). Then a couple hours elbow grease with a scrubber ending with a sharp tip knife blade and my phone cam magnifier to carefully scrape the stubborn spots, and there were lots of those. So I didn't find an easy way but I got it pretty clean and kept the shine on the enameled sides. Really beautiful pan now and perfect for a 2 egg omelet!

Great looking pan, you did a nice job.
Glad to see you are using it.