This a perfect Example of what Glen is talking about,Couple yrs back I bought 10 slabs of rams horn (ebay).
When I got them they were perfectally Flat,I thru them in my horn box than forgot about them.
They all look like this today,I did not properly take care of them. They should have been Clamped in place till use.
They can be resurected,but you need to take care of natural materials.
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