I bought this replacement faucet for my kitchen sink last August:

Pasco #33310, 10" spout.

It's a cheap faucet but I think it's decent, and it uses washers, not
ceramic valves. I use the cold water much much more than the hot and
today I noticed that the cold water stem is a fair amount harder to turn
than the hot. I just took it apart and wiped out the inside but it's
still a lot tougher to turn. What might cause this and what can I do to
loosen it up? I thought about applying some water-proof bicycle bearing
grease to the threads but am concerned that this might contaminate the
water, which is my drinking water. Suggestions appreciated.

Dan