The amount of public money you can funnel out or funnel in by cash in hand is limited to actual cash in hand. The level of corruption at the highest levels are

The amount of public money you can funnel out or funnel in by cash in hand is limited to actual cash in hand. The level of corruption at the highest levels are on the order of a billion euros. I am not sure if you can get even close to billions of euros in corruption using only cash.