Remove the showerhead. Soak it in a bowl of vinegar overnight. If it’s stuck, use cursing and a wrench (politely).
By morning, the calcium will be dissolved soup. Rinse well. Reattach. Your shower will spray like a rainforest again.
Quirky fact: If you don’t clean it, the build-up can host bacteria. So you’re not just scrubbing crust—you’re preventing a tiny soapy zombie apocalypse.
