Spit naturally dissolves, so it cleans well, and fast too. It’s not not harmful to any common materials afaik, it’s always immediately available. You need some way to wipe it off of course, just like with any other cleaning agent.
Just don’t let others see you, cause they’d be grossed out.
(Well it might be a little unhygienic, which is why it’s best as a quick/temporary solution, and you can do it properly later)
I have feelings on ‘both sides of the aisle’, but I used to be more grossed out about other peeps unhygienicals. I think that got less and less, because my view of the world around me has become dirtier and dirtier :). Now it’s like, what can 2 trillion bacteria even add to the scale? it’s all bad anyway!