I've installed an Enb. Given the fact that it gets installed out of the data folder, how should I clean the 'game' from all those files belonging to enbs?

Delete all files that you placed in you're oblivion folder that came from the ENB, check the zipfile to know which files the are.

it would be better if one could do a screenshot of their own folder, so I can remove everything that shouldn't be there.

Removing those one by one is going to be time consuming, givne the fact that some ENB have over 40 files

Just reinstall it and hit delete.

what do you mean?

By the way, have you any suggestion about ENB?

And last question: does it have sense to use a weather mod, if you have an ENB?