http://xmr.nowherejezfoltodf4jiyl6r56jnzintap5vyjlia7fkirfsnfizflqd.onion/opsec/haveno-cashbymail/index.html
To recap the recommendations we have the following graph: Here bob puts the cash into a mylar bag (to disguise the cash), which gets put into a tamper proof bag (that way, if alice tries to open it, it'll be easy to see), then bob puts it into at least 3 envelope layers with custom markings inside each layer (again, as anti tampering measures), and then putting it inside the tracking envelope.