if it's just a few stray frames throughout the video (and no more than 3 frames like this in a row)
then i would try using the mask feature in vdub. select the offending frame, and choose to mask them.
if this is all throughout the video though, ya may not wanna try it. could look choppy :/
KioAtWork: I'm so bored. I don't have class again for another half hour.
Minion: masturbate into someones desk and giggle about it for the remaining 28 minutes