It seems the faucet is mostly sending outputs of 0.0001 CLAMs, worth roughly a hundredth of a US cent each. I was wondering how best to deal with it. It costs more to spend than it is worth, and so the logical response is to never spend it, and to set a minimum deposit amount. Any deposit less than the minimum would be considered a donation. I ended up changing the hot wallet client code such that it never spends the dust outputs, but instead merges them whenever the wallet stakes. That is free to do, and so the cost of handling the dust is passed on to all the full nodes in terms of bandwidth and storage, but at least the UTXO set isn't being polluted.

Here's an example of a staking transaction tidying up a bunch of faucet dust.

I spoke to Kef about the dust from the faucet. I recognize that it makes no sense to ask people to stop spamming the blockchain. Maybe Kef/BAC would comply, but the next guy might not. We can't trust that CLAM users are going to be responsible. Better to limit the "damage" they can do, if such limiting is needed. Currently I'm not sure it is. Individual recipients of the dust can refuse to honor the tiny deposits if they don't want to deal with it, and maybe that's enough. If there ended up being enough dust that the blocks fill up a fee market will presumably develop, as it did in Bitcoin.

Personally I wasn't going to even bring the subject up, other than asking Kef if he can aggregate users payings into larger amounts and set a minimum withdrawal amount for the site. But since both the faucet and the subject of fees preventing spam both came up in this thread recently I figured I would mention it.

Edit: I should probably be clear that I have no problem with the faucet site. It's just that a lot of its outputs end up at Just-Dice, and they had been causing technical trouble until I found a way of dealing with them. They'll still be bloating the chain and the Just-Dice hot wallet, but not the UTXO set any more.