When he was president, some of the things he did in the campaign were not pursued by the DOJ because they felt that it would be hard to prove criminal intent. So we know that he's done stuff that would be criminal if he wasn't too dumb to know that it's criminal.

And we know that he's been successfully sued for fraud for Trump University.

So he's certainly not clean.

We also know that the accountant for Trump Org has pled guilty to tax fraud. So we know that criminal activity has been carried out in the running of his businesses.

And we know that he pardoned a whole stack of criminals that we worked with. While that's legal, it is straightfoward that he is not clean. Even without him pleading the 5th over 440 times,i n his NY deposition. Which is an admission of guilt.

With regard to the OP of this thread, he's under investigation for espionage, for perversion of the course of justice and for illegal document control. Despite the title, none of the 3 sections of US law that the search warrant sought evidence of depend on the classification of the documents. So if by "clean" you mean "has organised a loophole through which to sell senstive military information to Russia, Saudi Arabia and/or North Korea", know that he certainly has not.

But in either case he's not clean. Selling the country's military information to its enemies would be dirty even if legal.