DE or Repurpose Mastery Tokens

With the massive cost of mastery tokens, champ balance changes, and champ reworks, some champs that were amazing at one point either fall off to unplayable or to some other champ you cant recognize anymore.

IMO let us DE mastery tokens into some crafting material, ideally to curb the cost of mastery upgrades.

IE - Upgrade to M7: 3 M7 tokens + any of: BE Champ Shard Any 2 of other M7 tokens to upgrade the mastery level

2 M6 tokens + any of the same above to get to M6.

I have a bunch of random M6 and M7 tokens for champs I dont forsee being able to get tokens for in awhile and having a bunch of random mastery tokens always sitting in loot is ugly