It is always advisable to follow the brand manufacturer's instruction, some of which might be based on the materials used in the waders. Some recommend powders, some don't specify but call for a mild detergent. Stay away from fabric softeners and anything but the mild detergents. I wash mine once a year.
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I have used the Nikwax products with good success on jackets, other waders and it works good.
I also have had very good results with this from everything to Gore Tex to the various other types of breathable materials. It's also great to use on fleeces, layers and soft shells. The list of materials it can be used to wash is endless, look at the label or their website.