Hi, Francesco!
The issue with accents is determining whether they’re actually broken or just appearing broken.
My suggestion is to use the i2id and id2i utilities to convert them to plain text. With a text editor like Sublime Text, you can assess the situation and, depending on the case, convert or batch-edit the accents. Depending on the size of the database, it might be better to reimport it.
Unfortunately, you’ll have to figure out why the accents look wrong. Since I’m a native speaker of Portuguese, which has many accents, I’ve experienced all kinds of situations, so it’s hard to say what the best strategy is for your case.
ABCD Global