RCBS Competition dies were sold in the wooden box years ago, I have come across some that are new in the box for sale recently, they are good dies and were sold at a premium price.
Sure the build up on them wasn't dried up grease? I've had some old dies that have never been used and the grease has dried up till it's a solid mess, took a bit of cleaning but with a bit of work they cleaned up and looked like new dies.
Not sure what your problem is but if the dies faulty RCBS will possibly replace the die, I've had them supply parts and wanted to pay and they instead supply them free with free shipping.
Better service than I've ever had from Redding.
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