SuperDave 
Im not saying all cat buyers are scammers, but like everything else in business there are good people to deal with and bad ones. Atleast i know if i process them myself then i am dealing with a good person. =)
If you are going to sell them to a cat buyer/ ship them. You need to cut them as close to the brick/material as possible without cutting into it. I use a tape measure and a paint market to transfer the line, then cut about 1/2 inch back from it.
If you are decanning use the same method. The next step after the ends are properly cut is to do 1 or 2 cuts legnthwise. Usually 1 cut is enough then you can pry it open enough to get the bricks out. Somtimes i have to cut both siides. I use a chop saw to prep the ends and an angle grinder with cutoff wheel to do the legnth cut. WEAR SAFETY GLASSES.
Another method if your going for crushed material is to rod them out. Put them in a vice and use a stick of rebar to bust up the ceramic. Faster process but yields lower prices than intact bricks, for some reason buyers like seeing intact bricks.
if it all works out you end up with a box of bricks that looks like this:
http://www.ebay.com/itm/SCRAP-CATALY...item19d217d565
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