Faucet stem stiffens (harder to twist)

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
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Dan Musicant wrote:

Try some food grade silicon grease. You can find it at any scuba shop. We used it on scuba regulators as it was nontoxic and would not break down rubber like petroleum products will.
Silicon spray is NOT the same. You want the silicon grease.
--
Mortimer Schnerd, RN
mschnerdatcarolina.rr.com
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"Mortimer Schnerd, RN" <mschnerdatcarolina.rr.com> wrote in message

Will Silicon spray break down rubber ? I always thought NO, but my buddy who is a forman at a plastic's factory says it will. Tony
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