How do odour-abating insoles work?

Chris - Most of them have got activated charcoal in them. All that means is that it's charcoal with a big surface area, and this means you've got carbon, which can soak up noxious odours. So you have something that can lock away odours, that's the first point, and it will also do another thing, which is soak up water.Your feet squirt into your socks something like a quarter to half a litre of sweat every day. At the same time, you've got skin cells falling off at the rate of thousands every second from all parts of your body, but your feet especially because the skin on your feet is a bit thicker. So what you've got are all of the elements of the perfect microbiological or bacterial banquet going on on your feet: you've got food in the form of dead cells, you've got water in the form of sweat, and you have warmth. All these things add together to very active, hungry bacteria being well fed. Consequently, they produce various chemicals, some of which are whiffy - smelly; they're volatiles. But if you put these odour eating things into your shoes, they soak up the water for a start, which means that there's less to keep the bacteria lubricated so they don't grow as well, and they also soak up some of the noxious gases because they have a big surface area and they can adsorb those materials, which prevents them from being so pungent. So they work in a number of ways, but that's chiefly how it does it.