timemachine delete old excluded data

I got a problem with timemachine and I would like a better solution than to delete the whole thing and do it completely new. Because I'd loose so many incremental backups I might need.

I didn't properly exclude enough and now it complains about too little space.
Now I excluded another partition that doesn't really need backing up and a folder with temporary test data that grew to 40+GB in size.
Excluding it did reduce the necessary backup data a lot. Quick small now indeed with only 45 GB.
It still keeps complaining because it doesn't remove the old big folders from the old backups and has only 15GB space left.
How do I tell it do delete all the excluded stuff from old backups and keep only the stuff that is still included????
It seems not smart enough to figure that part out itself.

Rather urgent I don't want to be without backups for long.

 

@shinobi-81 It doesn't do that. It keeps saying it fails and it isn't what I want anyways. From the data I need backed up I want as many incremental backups as possible. That stuff also doesn't need all that much space.

Thanks Weaselboy I hit delete all backups of the one excluded parition.
now I got one more question how do the same with my folder full of test data. It is hidden unfortunately and I cannot seem to find the checkbox to view hidden folders in timemachine.

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I created a sym link to the hidden folder in my home directory and went from there. Still it would be nice to know if there is a non terminal solution to the hidden file problem.
I usually use Pathfinder and don't have to bother with that crappy finder. Finder is really probably the most pathetic thing in OSX.