A WebmasterWorld thread asks the question most SEOs and webmasters try not to ask in a public forum. After a penalty is lifted, should you go ahead and remove your disavow file or even remove some of the links from the disavow file?
Why would you do that?
Well, some of those links may have helped you. It is hard to know exactly which URLs you disavowed are helping or hurting your site from ranking.
So playing the game of add and removing specific URLs from that file can be slow but some may be playing it.
The overall feeling in the thread is not to remove the disavow file because Google may take a look again and then penalize your site again. But some feel you should experiment.
I doubt Google would penalize a website for undisavowing links because there are too many ignorant webmasters who get scared, overreact and disavow 100% of all links (good & bad).
I do think that undisavowing spammy links is not the smartest idea but I haven't tested it myself.
Forum discussion at WebmasterWorld.
Update: Matt Cutts tweeted, no, you should not remove the disavow file.
@rustybrick No.— Matt Cutts (@mattcutts) October 15, 2013