This is the "turn it off and on again" of plumbing. If your kitchen sink is slow because you poured bacon grease down it, this works surprisingly well. The high heat melts the fat bonds.
Use a cup or bowl to remove as much water from the sink as possible so the solution can reach the clog directly. how to unblock a sink
(Great for maintenance, useless for major clogs.) This is the "turn it off and on again" of plumbing