> An efficient money laundering rate is anything north of 50% (100 dirty --> 50-70 clean).
That's supported by what I read in "Kingpin: How One Hacker Took Over the Billion-Dollar Cybercrime Underground" by Kevin Poulsen. Book's about Max Butler alias Iceman who ended up as in the higher echelon as vital gear of a carding gang. They'd have people who'd shop and resell the items instantly, as if new. The shoppers also need to get paid, obviously.
Blockchain's entirely public, so Bitcoin is terrible for money laundering. Not any better than USD.
Monero is apparently anonymous though. Though I take the term anonymous with a huge grain of salt since its always a relative term, not an absolute binary flag.