When we arrived in Bagni di Lucca in October there were sweet chestnuts lying around all over the place. They come in little pods of 3 or 4, and are protected by a viciously spiky shell, which is much more forbidding than the leathery coat which protects the horse chestnut. We haven't actually gathered any (and I think they need to be dried or at lest matured in some way before eating), but the quality of the ones we've bought is way better than anything I've managed to buy in the UK or Spain, with mouldy ones or ones which consist almost entirely of skin being the rare exception. I suspect that the problem is inadequate storage of the nuts.
I don't have any tips, other than to pass on something which Sammy pointed out to me. It's best to cut them across the way rather than from top to bottom, as they open up better this way while roasting.
