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 hate that you are right.
Anyway, I get annoyed when people do that. I don't like people licking their fingers before turning a page. I don't like mothers wiping their children's faces with their spit. I definitely don't like touching surfaces that have been "cleaned" with the saliva of someone who has God knows what disease. And so on.
Maybe I have been "hygienically damaged" during the pandemic.
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!