Deleting Message from SMQ2

Hi,

Is their any other way to clear all the messages in the inbound and outbound queue of XI (like XBTIXXX1 and XBTOXXX1).. I tried deleting it from SMQ2 by selectig the queue .But i have 755617 messages in the inbound and outbound queue. So deleting each queue takes a very longer time.

And i won't be able to reprocess again using the report "RSQIWKEX "..because there are around 20K messgaes .

can you please help me ?