Ivory tends to crack over time. Like decades and decades. That drying out can be arrested just by a little care. The most recommended treatment is to rub them with Johnson & Johnson baby oil. Not dripping, just rubbed in on a regular basis. Gun grips are often subjected to the storage conditions the owners think are correct for the gun itself. Dry isn't good for wood or for ivory, or worst material of all, pearl. Ivory is strong and very easy to work. I love the stuff, but understand it does have some problems. The worst is legal. About 1971 I think they outlawed trade in the stuff. You can't import it or even sell or transport it across state lines. Except everyone does. It just feels good in your hand.
Its not recommended for daily use and particularly hard use. Ever seen the right side grip on an old service revolver. Cops apparently had a bad habit of rubbing up against brick walls and bashing their gun into cars door frames. Really old ivory tends to check and cross crack. Those guns weren't taken care of. Think the baby oil again.
I'd suggest the OP and anyone else interested in elephant ivory take a tour of a large gun show some time. I can't speak for the small regional ones. Here in the center of the country, we have things like Louisville, OGCA, and Indy. At those venues you'll see ivory and guns with ivory on them that look spectacular.
Its not the sun that turns the grips yellow. Its the oil in/from your hands. In the past piano keyboards had ivory keys. The owners always kept the cover up so the sun could shine on them, keeping them bleached white. Its why many of us handle the guns and then bury them deep in a safe so they don't get the sun's magic. Very minor yellowing is considered great. Much more is an indication of artificial aging. Often with tea to make even nearly new ivory look like its 100 years old.
If you meet an ivory workman like Don Collins, ask to buy a scrap or two. It allows you to file a little and see what a great material it is.
And of course I have a story. Long ago, like around the turn of the century, i was at a gun show. A vendor I know well had a Randall kit knife for sale. Yes, Randall used to sell kits so you could finish your own knife. They aren't seen very often. This one had a problem. Its fairly well finished but the original owner stuck a nice piece of what appears to be elephant ivory on it for a handle. And the day I bought it, it had a crack from stem to stern in the handle. It was an open crack and wide enough you could stick the edge of a dollar bill in the crack. There was also a little dirt in the gap. So I negotiated the price down (read cheated the guy) and took home a very nice knife. One almost never seen with ivory. And just for the fun of it, I scrubbed the handle and especially the crack with warm water and of course, Ivory Liquid. I scrubbed for a while without fear. When I finished, I could see a difference my work had caused. So I took all my junk down to the dungeon where I kept stuff in that house. It wasn't a dry basement by any stretch.
So I put the knife and sheath aside. I then asked my wife if we had any baby oil and she laughed at me. Our boys were grown and gone. So I asked her to pick some up when she went to the grocery. She promptly forgot. So did I. Long after, maybe a year, I saw the knife again and realized I hadn't treated it. So hoping for the best I picked it up. The crack had swollen itself shut. As in you had to look to even see where it had been. And I remembered the story the seller had told me. He'd had it in his gun safe and when he picked it up, he saw the crack and was heart broken. He'd ruined a very nice knife so he decided to dump it. I was the dumpee. And by luck, I'd taken the best cure. I still have the knife and I still like it. I'm a little worried now because this house has a much dryer basement. Last time I looked it was still OK.
The worst treatment for a gun with ivory is to use it to nail up fencing or wanted posters. I don't even think I'd recommend it in the intermountain west. If your relative humidity is normally under 30%, its dangerous. Worse is taking the grips on and off the gun very much. The best course of action would be sending it to me for safe keeping!
