Can Pickpocket kill a Gold token?

Yes, but we see why you’d ask. The rules use a “NULL” system for values that aren’t available, such as the Might of a unit that’s been removed from the board. The unit is gone and the information is missing, so you can’t do any calculations or comparisons with it (not even “is it no more than 1?”). That system could reasonably be applied to the costs of tokens, but we feel that results in unintuitive situations, like not being able to kill a Gold token with Pickpocket. After all, the token’s not missing; it just doesn’t have a cost because it doesn’t need one. We’ll be updating the rules to clarify that the cost of a token can be treated as 0 for all purposes.