JL, never seen any written standards for sending asbestos samples through the post. However, the process adopted by my previous employer included small air tight plastic packages for each individual sample inside a larger air tight package, all contained in a jiffy bag and sent by recorded post. Never had any issues with this process.

Typically these samples were smaller than a finger nail and although a hazardous material we are not talking about a highly dangerous substance like... novivchok. 

Originally Posted by: johnmurray

The initial post was right, for Royal Mail; Asbestos samples must be encapsulated in resin or glass. Try a courier company. Funnily enough, Royal Mail also refused to accept a biological sample in a UN3373 package....although said packaging contains sample absorption and protection. You may not like their response if the contents are revealed.....

I belive this might be a case of the royal mail being happy to courier the samples as long as they dont know whats in it, they must handle dozens of samples a day. I agree with the first post that if packaged well its a relativly low risk, just seems odd that there isn't a written minimam standard for couriered packages to meet.