There should be another couple of ways to 'temporarily remove' corrections.
If you want to keep your own corrections but remove other people's, then with the unit connected to Home on the PC, go to Home's "Tools" menu, then "TomTom MapShare" - "MapShare preferences".
From there, you can select a "trust level" which at the strictest setting should have the effect of hiding any corrections from other owners (but not TomTom themselves) but should keep your OWN corrections in use.
If you ONLY want to remove your corrections, then I think it's the file called UserPatch.dat you need to delete.
In more detail:
Downloaded MapShare corrections from other people seem to be saved in 3 dat Files; 'ServerNameIndex.dat', 'ServerLineIndex.dat' and 'MapServerPatch.dat'.
For a user's own corrections, it seems that a file in the map directory called 'MapUserPatch.dat' refers to changes in another file (in the root directory) called UserPatch.dat which actually contains the details of the changes.
If you delete either file they recreate themselves but if you do not have a matching pair you seem to lose the changes.
Before now, I have removed the root directory file which removed all my changes. When I restored it, my changes were not visible again until I also restored the map directory file.
It also needs to reboot after copying the files before the corrections become visible.