You probably have twenty but a hardware store has many more.

Emergency room. Difficult extraction. Any bright ideas on getting this out?

I hold what you wear when it’s no longer clean, or slow your progress without being seen.

I am fast and slow. People know when I pass, but do not see me. You may hear me, by the noise of a tick tick tick. What am I?

Indoors, but outdoors, encased by walls. Open sky, plant life, adjacent to halls. Not a greenhouse or the front or the back yard. The prosecution rests; don't think too hard.