As a courier mate I know about rank helmet linings, after it gets wet it stinks, so what I used on my old helmet with non removable liner.
The good old dish washing liquid, if you like even the nice lemon sented if it so turns you on. Hot water and leave to soak for half hour, rinse well.
Now to dry the sucker, there aint no way quick to dry it out. The best I have found is the old kitchen urn, a couple of towels on top of the urn, and 24 hours later nice and dry, smelling nice clean. But I have since bought a helmet with a removable liner just for ease of washing and drying it.