If you have calcium build-up on your faucet or showerhead, look to vinegar. Fill a plastic bag halfway with equal parts white vinegar and water. The bag should be big enough to submerge the faucet head or showerhead fully. Secure the bag with a rubber band or zip tie, ensuring the seal is secure so no vinegar leaks out. Let that sit for a minimum of 30 minutes, or overnight if you're working with a showerhead that doesn't have a sensitive vinish like brass, gold, or nickel. After you remove the bag, you can scrub with an old toothbrush, rinse everything off, and wipe it down.