Can you point me towards Scotchgaurd on the net and do you use it on all your footwear?
Basically all Scotchgard is the same, whether for fabric, carpet, clothing or shoes. It is a flurocarbon and comes as a water or solvent based product. The water or solvent is simply the carrier that allows it to be sprayed onto the items in question, which once done, evaporates leaving the flurocarbon shield on the item which is partially absorbed.
This coating can last for up to 3 cleans if using just water. If you clean with a detergent a re-application will be neccesary as most of the flurocarbon will be removed.
When my Hedgehogs get muddy, I remove the footbeds and let them dry thoroughly before giving them a good brushing with a semi stiff brush. This removes most of the soil and usually does me for the next walk. If they get ina right mess after a few walks and the build up is not removed sufficiently with the brush, I run them under the tap and just work the water in with my hands.
I then stuff ball of newspaper into them to retain shape and absorb most of the water, leaving it in for about 24 hours.
Occasionally I have put them in the washing machine as I do with all my running shoes, however I am not sure this is a good idea for GTX lines shoes.
You can get the scotchgard spray from Amazon or most good shoe retailers.http://www.amazon.co.uk/Scotchgard-Water-Repellent-Shoe-Protector/dp/B005MY4PPK