Hmmm, I found an interesting idea about this just now...
http://www.freepatentsonline.com/5217623.html
The patent just added xylose sugar to the material. The half-life of the cyanide at 25 degrees Celsius is only 1 minute! Pretty impressive.
Apparently any aldose sugar will work.
Aldose sugars have an aldehyde group on them. When you mix the Xylose with the cyanide, you get none toxic acidic sugar. So I guess the cyanide radical is oxidising the aldehyde to an acid and the nitrogen comes away as gas?
Did I say I'm impressed?