Cob: I absolutely cannot believe this!

[sd_fenton at cox.net]

I would think that diatomaceous earth would be perfect. I first read about 
it in Countryside magazine http://www.countrysidemag.com/ and have since 
found several articles online, which I'll attach.

Basically, I'm thinking you could mix diatomaceous earth with your cob (not 
too much, as it's very "silty"). Be sure to always use the "food grade" 
diatomaceous earth which has a silica content of <1%.

Diatomaceous earth is completely nontoxic and is the fossilized leftovers 
of ancient microscopic organisms.

http://www.usaemergencysupply.com/faq/diatomaceousearth.html
http://www.ighawaii.com/naturally/naturalanimal/diatom.html
http://www.eap.mcgill.ca/Publications/eap4.htm
http://www.internet-grocer.net/diatome.htm
http://ighawaii.com/naturally/naturalanimal/de.html