madness

As mentioned previously, using a washing machine is fine, but don't use any soap/detergent that's not recommended for use on goretex. If it's safe for goretex it'll be fine for any other waterproof. I've used Nikwax products on goretex jackets for years and had no problems. Be aware that they will never be as good as when they where new. As far as I'm aware you can't buy the DWR (durable water repellent) chemicals that waterproofs are coated in when new. Don't forget to follow manufacturers instructions to the letter.