I have a forum that has been blacklisted by adsense for invalid clicks and that was about 4,5 years ago. The site has a labout 25k discussion with more than 1.5k users so i'm thinking to buy a new domain and redirect everything with a makeover content. would it be safe to use the same data ? at the very least I would like to retain user database, if the content is no good.
It is not a good idea. You can't easily cheat Google. Actually you have to face to the same risk again; invalid clicks activity. You should be careful because forums have relatively high probability to get invalid clicks.
If you move everything to a new domain, you'll lose the aging domain benefit, but this will come back. As for the backlinks you can always make a redirect to the new domain. If you're sure that your content is ok, that no invalid click will happen again from dumb/angry (ex)members then ok.. But it is risky in a way.. Well, if you think the eanrings are worth the risk (don't know if it's a big risk or not) then why not, nearly 5 years.. many things have changed since.