They have a DWR treatment to the outer leathers, so when the leathers get muddy it's a bit of a dilema with regards to caring for them.
I can clearly clean them with a wet sponge, but water + leather = rot/hardness. Also, by doing this each day I can't imagine the DWR will last more than 3 days...
Having to polish them after each outing, treat them etc also rather defeats the point of them being supposedly rugged.
Nikwax stuff very good, or use the stuff the brand of boot sells too, as most big walking boot brands sell stuff to especially service their leather outers to the boots. Grangers stuff too is fairly well liked.