Are my bitcoin clean

[OYEDEMI01]

What are dirty coins?
If anybody who has Bitcoins makes a crime (for example the owner of laser.online that stolen Bitcoins). these Bitcoins are dirty.
So such a person tries to get rid of them. For example he tries to change them into Fiat or buys Altcoins. If I am the person who gives this person my Altcoins and this person pays me with the dirty Bitcoins I have now this Bitcoins. No I have dirty Bitcoins. (Bitcoins with a dirty source Bitcoin Address)

Qurstion
1) Are there exchanges who have a black list of such dirty Bitcoins. A
2) And if a user who has such Bitcoins transfers them to such an exchange will become suspicious.

3) could there be a system tocheck, how clean my Bitcoins are?

I am thinking aloud after being scamed by laser

[Cointastic]

There are laundry systems which make this difficult. 

[akmittal]

It is very important, the source of income it should not be earn with malicious practices. Bitcoin must be purchased from recognise sourse.

[masudginanjar]

"I am thinking aloud after being scamed by laser"
what do you mean with laser?

if bitcoin enters the Exchange, it does not need to find out Bitcoin from where it gets, because usually the Exchange requires KYC only.

[kent47400]

1. As is known, Yobit is a less preferred Exchange for token holders, because the service of Yobit is less friendly to all its members.

2. It is not suspicious that it is good for the Exchange because every Bitcoin transaction always requires a fee for the Exchange.

3. Bitcoin cannot be counterfeited, when one Bitcoin has an A then the result will be an A, and cannot be duplicated.