With mixer, you can remove the traceability from your known bitcoin address.
Bestmixer is seized by the authority and I have updated it in the OP, you probably have missed that. Other one, bitblender has stopped its operation.
Here is
a more comprehensive list for you.
Mixers don't necessarily
remove the traceability of your bitcoins. They can certainly make them harder to trace, but adversaries
are always trying to break them. Not all mixers are created equally, either. Some mixers employ much better techniques to evade blockchain analysis than others, so it's worth doing some research to find the right mixer.