After a long climb your Gore-Tex may be pretty grimy. Mark Serjak did a little snooping and queried ARC'TERYX (tip forwarded to us by Leonard Russell):

Query:
"I have an ARC'TERYX Alpha SV jacket - by far the BEST shell I have ever had - my 2 year old North Face XCR jacket is not even close! I hear many opinions concerning the care of the jacket - one is that you rarely wash it. I was using the Nikwax Tech Wash - I use it at half strength. How often should I wash it? Many people tell me that the waterproof layer will come off if I wash it more than once a year or so. However, with climbing in the Washington Cascades, I often come back with dirt/sweat on the jacket. What do you recommend? Also, what is a good soap to use on it?"

Reply:
"Thank you for your interest in ARC'TERYX. Whoever has been giving you advice has been way off! You want to wash Gore-tex as often as necessary - dirt and sweat clog the pores and cause it to become less breathable. You may not need to use Nikwax every time - if water is not beading up on your jacket the way it used to, then it's time to use Nikwax or something similar (your retailer may be able to suggest other alternatives). Make sure you double rinse your jacket after washing and dry it in the dryer (no dryer sheets). The DWR coating (the thin water repellent finish) does wear off eventually but is easily replaced with Nikwax or something similar. You can use regular detergent or a product called Techwash when you wash the jacket - Techwash isn't necessary but some people feel it helps to make the DWR last longer. The major rules are: wash when dirty, double rinse, dryer, DWR when necessary."
-Bryn Coape-Arnold, ARC'TERYX