Do we speak of the in-game VaM file browser? Then the answer is a clear "yes-no".
If you may already know, there is those gear-wheel symbol in the lower edge of many files. If you click this, you can delete stuff one by one. There is also the AddonPackageFolder where you can find and delete the entire downloaded Var file(s). This is the "yes". But deleting some stuff with all those cross references and dependencies going on, can surely mess up something. This is the "no".
Unfortunately AFAIK till now there is no easy way to see what can be deleted without issues or not, especially if those stuff is part of a Var file together with many other things. This is a common issue, especially if you download a lot of stuff and therefore easily loosing the oversight.