[ Don Teach wrote in 140103 MMDigest:

> For years many restorers thought that the leather had been treated
> with some sort of egg white mixture.  It turns out that the leather
> was treated with nitrocellulose.  This product can still be found.

According to this link  http://en.wikipedia.org/wiki/Nitrocellulose 
nitrocellulose is a highly flammable material also known as "flash
paper" or "flash cotton", frequently used by magicians for flash fire
effects.  I rather doubt this would be suitable for sealing leather
pouches.

John Grant