1) Go to 'game' and then 'add event definition'.
2) Choose 'begins with' and then input text that begins every line you want to cut out. For channels, just put '['.
You have lots of options here - these 'events' can do a lot of things for you, from coloring text to playing sound when a certain message is recieved. You can also set the 'scope' - that is, you can set an event up to work for a certain world, or to be 'global' and to work for every game in your address book.
Here I'm telling it to only work for the game I have called 'XMM2 - Natalie'. I've also chosen 'when incoming string begins with' and set it to [ - this means that it will do the action I choose every time a line begins with '['. I do this because I want to cut out all channel conversation. If I wanted to just cut out things on public, I could enter 'begins with [Public]' instead, or anything else.
I could also tell it to match text exactly ('is') or to do something whenever the text shows up anywhere in the line, not just at the beginning. Those are usually more useful for things other than log editing.
3) Check 'omit the line of text from logs'. Click okay!
You can do other fancy stuff with these checked boxes - tell it to set text color to bright yellow whenever text 'is Natalie', play a sound whenever someone pages you 'WAKE UP!' - lots of options.
4) Go to 'preferences', 'configure', 'log options'.
5) Check 'extra carraige return between lines'.
This makes sure there's a space between every pose. You can also choose to 'timestamp' your logs (have the date affixed automatically), and you can set your preferences for what date format this uses under 'preferences' , 'global preferences'.
Now you're all set up for easy log-cleaning! To log:
1) Choose 'start logging' from the 'file or 'connection' menus, or use the icon indicated above. You can also type '/log' and hit enter to get this prompt. Say 'yes' to the question!
2) Choose where your log will live and what it's called. Be sure to remember where you put it!
3) Saying 'yes' to this tells your log to go back and get everything that's in your window (called 'backlogging'). Saying 'no' means that it will only log anything that appears /after/ you chose to start logging.
And that's it! You should now have an easy-to-edit log on your harddrive! Remember, you can tell SimpleMU to cut out whatever you want - so you could also tell it to ignore anything starting with (OOC), anything that contains the words 'pages, "', etc. It's up to you! Play around a little, see what you like.