Cluescroll untradeables should be unlocked via RNG. As is the nature of clue scrolls.

I think its a pretty odd idea that clue scrolls, something that are completely RNG driven, are now being given as rewards that are only obtainable through a long grind. Clue scrolls are more meant to be a break from the grind with the possibility of getting an awesome reward. If anything there should be a "clue cape" reward that is obtained once you've "mastered" clues by completing a set amount of each kind. That seems more fitting in my opinion.

To not interfere with any chances of getting a 3rd age item or the like, the untradeables should just act as an additional reward from it's own drop table, similar to how boss pet drops work.