After iconizing, there is nothing we can do with the emblems, but we keep winning them anyway from various favor quoins, donating, and so on. They cannot be sold and if you already have and icon, the bonuses that an emblem give are useless.
So, I propose to do the following: have a limited time of uses for the icon, say 1000 reveres, reflects etc. After 1000 uses (or whatever number seems appropriate) the icon gives some sort of a signal, a flash or a shooting star, or a pithy saying or whatever and then disappears. The sign I think is necessary so the owner doesn't think he dropped it or lost it somewhere.
Hehe, the sign before disappearance can be the god of that icon appearing and being frightening and whatnot for the abuse of the icon or something, so he takes his icon back and his benevolence can be obtained by donating enough to the shrines until you get the next emblem.
On the other hand, as a side note, I would certainly prefer a funnier or more playing-down-the-religion-a-bit approach, because, frankly, the whole religion thing is kindda creepy; it's not appealing to the religious folks on the account of having a wift of blasphemy and it certainly doesn't seem to do the trick for the agnostics either. So the only way - I think - to keep from offending people, because religion, even in a game, like it or not, is a very personal thing, is to playing it down and making it humorous. And we can start that by not calling them gods, but Devs or the Bigguns, or something like that...