
mardaddy |

It all depends on the context of the delivery. Spirit of Glass (Alchemy Manual - 35gp per dose to buy) is basically powdered glass that turns injury into contact, but it may or may not work with the context of how the player is conceiving the delivery.
Putting it inside a shoe, socks, shirt or gloves with the injury poison works, but trying to use it externally with a gloved handshake will probably not.