My favourite thing to do is take the eartip off and kinda lightly suck on the actual speaker thing, like a weird straw. Makes them sound like new and gets dust out from inside
Google recommends not using alcohol. Alcohol is good for cleaning PCBs and charging contacts on devices, but not so great for the plastic body. It can also damage the silicone eartips.
tl;dr: Remove eartips, wipe gently with a lint-free cloth, add a small amount of water if you're having trouble scrubbing anything (without getting water inside). If you have Pixel Buds Pro, they also recommend using an adhesive putty if you're still having trouble removing any debris with the cloth.