Thread: Ну...

What does the following sentence means?

Ну, дык. Шарит, плесень...

I can't grasp it

"Ну" here means "well". "дык"= да/так (slang)
So it may be translated as "Well, yeah" or even "Sure!"
"Шарить" = to grasp (slang)
"плесень" here is unceremonious (friendly or rude, depending on context) form of address.
Well, if you grasp it, it could be said about you.

(Sorry about my English. May be somebody will explain better).

Yep, something like:

yeh, sure, that scum understands that.

That is a very special, and quite rude slang.