MPost wrote:

I just removed and reinstalled the shutoff valves under a bathroom sink and
the washers in the valve stems of the faucet itself. After doing so,
whenever I let the sink sit for a little while, like overnight, I get
rusty/yellowish water for the first few seconds after turning on the faucet.
The rust clears up after a couple of seconds, but I can't figure out why
doing what I did is causing the rust. Any ideas what I should check? The
only metal pieces that I actually replaced were the screws that held the
washers in place. Do I need to use a special screw for this, like a
stainless screw? The ones that I took out were pretty badly corroded.

Brass would be more likely what the original were. If you used just an
ordinary steel screw it will rust and likely by the time you need to
repair again it'll be near impossible to remove...SS would work as well,
though, you're correct.