The shower head is one spot in the bathroom where you'll want to be especially diligent about cleaning. After all, you bathe using the water that comes from this spout, and if there is an extra buildup of grime within your shower head, its only going to come out through the water that you're using.
Bathrooms are some of the dirtiest places in the house because this is where residents clean off the germs and sweat that has accumulated on their bodies throughout the day and overnight. Also, an improperly ventilated bathroom can produce a wide array of cleanliness issues as these places are extremely moist, and excessive moisture can produce harmful mold or mildew.
Although you can't see inside of the shower head without removing it from the spout, all of the hygienic issues that make the rest of your bathroom a haven for germs are only amplified in this hardware. Calcium and other minerals that may be in your tap water could build up in your shower head, actually decreasing the water pressure.
Since you have already begun your spring cleaning ritual, now is a good time to remove the shower head and soak it in vinegar overnight. There are many other mineral-absorbing plumbing solutions that can adequately clean out the buildup in your shower head, but if you don't mind letting it soak overnight, vinegar can effectively do the job. After your shower head has been soaked, gently scrub the inside and outside with a toothbrush to make sure any loose dirt isn't left behind.
If you notice that your shower head still isn't supplying adequate water pressure, there may be a larger issue with your home's plumbing. In this case, contact an experienced Washington, D.C., plumber like those at John C. Flood as soon as possible.