Mr Tinsby is correct - they are the plugs for the holes where the spinlocks would go.
This is the third time on this forum that I've seen this issue of finding them in the drain holes. No, they do not float up when the drain pan fills with water, as jmatta found out. This could have been disastrous if the water had overflowed into your cabin and soaked the alarm unit under your seat.
I'd love to know how these plugs keep finding their way into the drain holes. I'm at work now, but when I get home I'll post a screen cap from the parts catalog showing where they are supposed to fit.
Jaykay, hopefully you can retrieve the part from the garbage and install it where it's supposed to go.
