Every anon here, including lurkers, would have to drop everything and work 24/7 on foundations to thoroughly dig on slush funds.
The numbers are staggering, people.
As of 2014 (report PDF link below) there were 86, 192 foundations in the US.
Total assets were $715 billion.
http://foundationcenter.org/gainknowledge/research/keyfacts2014/pdfs/Key_Facts_on_US_Foundations_2014.pdf
The report is a helpful quick graphic, but the main takeaway is that it would be a piece of cake to camouflage some millions here and there under the enormous hiding place of $715 billion. Add offshore banks to the formula, and federal law enforcement (weaponized by Obama) ignoring the shenanigans, and it's practically perfect.
Especially if you commit as much wire, mail and tax fraud as the Clintons.
Refer to Charles Ortel for the utmost word on financial miscreance.