how to remove mixergroups from a snapshot

I am trying to retrofit an old project done pre 5.x and would like to use snapshot to handle various levels of ducking: full scene audio, dialogue, muted and as I tune the scene mixergroup I noticed that some other values are set wrong so I change them but now the snapshot is polluted by these changes and at runtime, player volume control get overwritten by the snapshot

How do I remove a mixergroup or a changed variable from a snapshot, you know, like a delete keyframe?

 

here is how it's done:
make parent mixe group that are only controlled by the snapshots
then rock it like it's 1981

alright not very modern so I logged two bugs on that:
870847 - unable to remove snapshot pollution, even by deleting snapshot (because we can't delete the last one and + is a duplicate, not a blank copy)
870848 - snapshot doesn't appear after creation, save project required