Mail Queue problem.

I am having problem with my mail Queue. it is seems to be bit "big" and it causing delay on delivery.

here is the qmhandle out put:
Messages in local queue: 1674
Messages in remote queue: 115

ppl. in the server are complaining about the delay of the mails.
when I checked the mail log i find many lines similer to this.

Jun 9 13:59:03 myserver qmail: 1086814743.888303 info msg 3474676: bytes 25597 from <#@[]> qp 18190 uid 2522
J

Jun 9 13:59:04 myserver qmail: 1086814744.010042 info msg 3474837: bytes 3861 from <#@[]> qp 18467 uid 2522

Jun 9 13:59:05 myserver qmail: 1086814745.265775 info msg 3474700: bytes 1978 from <> qp 18265 uid 2522

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What is this <#@[]> and <> where are they come from?
How can I block them?

I am running RH7.2 with Plesk and qmail installed.

 

 

 

 

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