Bitcoinfog works by mixing your Bitcoin (technically your Bitcoin are actually just encryption keys, and it is those that are mixed) within their pool of encryption keys from others that are using the service. I would advise withdrawing to a separate Wallet first so as you can be sure the Bitcoin have been withdrawn. We get too many messages from people stating their Bitcoin have left SR but never arrived at their destination, and it is always as a result of user error. You can read more about how BitcoinFog works on their site: http://fogcore5n3ov3tui.onion/ BitcoinFog have been around for quite some time, but please be aware that ANY site you send your Bitcoin to can abscond with them at ANY time. It is safe insofar as it has established itself as relatively trustworthy, but you have no recourse should they decide to just steal everyone's Bitcoin as other services have done in the past. blockchain.info also provide a mixing service but you'll have to check all that out yourself as I'm afriad I don't have the time to write about it here. All the information is available on their site, and indeed dotted around the Silk Road forums. Libertas