The steps of this instructable show you how to remove biological mysteries from your sink's drainage without using caustic chemicals that cost money, are bad to breathe, less fun and whose success as an unclogging strategy has a lot of uncertainty.
My bathroom sink is simple enough that the pipes and pop-up assembly do not require any special tools to take apart and put together. The only tool I employed besides my hands was an old tooth brush.
This job takes me about 15 minutes; less time than it takes to go to the store and back to buy those old chemicals.
I read that you can keep pipes from bioaccumulating by putting down 1/2 cup baking soda, then 2 cups very hot white vinegar, wait 1 minute, bubble bubble, then follow with 2 cups very hot water.