Does anyone have any tips on cleaning foul weather gear? My Musto jacket and salopettes are quite soiled. Fabric is Goretex. How do I clean them without damaging the fabric and weatherproofing?

I have Gill Goretex 10year old now and I have always washed it in the washing machine at low temp. It states powdered detergent and low spin speed (do not use fabric conditioner or one of the new 2 in 1 powders. Allow it to drip dry but before completely dry put it in the tumble drier to re-waterproof the fabric. Some marks I have not been able to get out completely but these are only a few.