[Every distribution I've tried] How do I delete messages in bulk?

[lists at kitepilot.com]

Hello Intelligence... 

Is there a GUI tool to delete messages in bulk?
Is there a way to do it with a shell script? 

The problem:
I get waaaaay too many (most times useless) messages...
The only way I've found is to delete one at a time.
When deleting 125 messages, it gets old pretty quick...   :( 

Could I do something like:
rm `find /path/to/msgs -type f -exec grep -li "from my network" "{}" \;` 

Can this be done in the GUI?
I guess that's an improvement I could write...   :)
Thanks!
ET 

PS: Back with SHR, seems to be working better now.
I installed:
0b76c9d620a36ea8a11ce510bc9e19f1  shr-image-om-gta02.jffs2
162ff7e58c7943a9d28cad9b6fb6bf3d  uImage-GTA02.bin.bin
 -rw-r--r-- 1  113508352 2009-07-21 07:16 shr-image-om-gta02.jffs2
 -rw-r--r-- 1    1832584 2009-07-08 16:21 uImage-GTA02.bin.bin
Can anybody verify (or explain me how to verify) that those are the ones I 
want?
What about the criteria to choose one over another?   :)