What is an easy way to clean a shower head?
Clean your shower head with vinegar!
This is recommended to do at least once a month to avoid accumulation of various tiny bits of matter/debris that can be found in your water. One simple way to do this is to secure a plastic bag filled with white vinegar around the shower head and secure with a rubber band. Let it soak for at least three hours and then run hot water through it to dislodge any further debris.