recently i discovered doing otc that its possible to buy dirty bitcoins from someone and then when you try to sell it on an exchange the account gets frozen 
does anyone know how to know if a btc is clean this ?
kind regards
does anyone know how to know if a btc is clean this ?
kind regards
If you are worried about this, just don’t do any p2p stuff.
Big crypto exchanges use complicated chain analysis tools to determine which addresses are carrying any “dirty” coins.
Since you don’t have the same resources as the big crypto exchanges, you’ll get fooled easily if a criminal decides to do business with you.
Then you’ll probably try to dump those coins on an exchange without knowing what they are and boom, here comes the endless questions about where you got those coins.
They’ll seize your coins and you will probably face some jail time unless you prove your innocence.