How do I clear a slow bathroom sink drain?

I would try boiling water and Dawn dish soap. My plumber has us do this for our bathroom, it helped with buildup. If it’s hair clogging it, you can get an inexpensive tool to pull it out. The bottom of this post we did on baking soda and vinegar talks a little about this https://chemistrycachet.com/the-truth-about-cleaning-with-baking-soda-vinegar/

Cover to overflow hole with wet paper towels. Pour some baking soda down the drain. Then pour some vinegar down. Immediately cover the drain with a cloth and hold down with you hand. The force of the foaming should push the clog through. Follow with hot water.

Hi Denny, you might first try what is called a sewer snake.....I found a plastic type gadget at DollarTree which is similar to the larger metal ones. It is a very long, narrow piece of plastic with "barbs" on each side. You place it into your sink drain and twist around and then pull out. When I did this I came out with a good amount of hair and "gunk". Do this a couple of times or as many as it takes to do it and come up with nothing attached to the barbs. Then I suggest using about 1 cup of baking soda sprinkled into the drain and a a couple of cups of white vinegar poured down the drain. Let the mixture set for a 1/2 hour to an hour and then pour a big teapot full of boiling water into the drain. This should help to make your drain work more quickly . If this doesn't help at all, I'd think that you may have issues further into your home's plumbing. Hope this helps! You could also just try the baking soda/vinegar recipe if you can't locate a sewer snake or the barbed device I mentioned.

There’s a plastic drain cleaner stick. Can’t remember where I got mine but they work great. They don’t damage, can slip past the drain stopper and those little plastic barbs grab hair and gunk.