If you've touched your earplugs with bare hands then saliva is the least of your worries ;)
It's part of why I wear the shield type ones, they don't go into the ear canal so no squeezing or spitting on required.
They only attenuate to 20db above 2khz but, with a good lid and a tall screen, I find that more than sufficient without preventing me hearing comms or the world (sirens) around me completely.