I do it in regex with notepad++.
Go to Search -> Replace , now make sure the Regular Expressions radio button is checked
If you have a keyword, for example KEYWORD1, type the following into the find box: ^.*KEYWORD1.*$
(In Regex ^ means beginning of line, $ means end of line, and .* means any old text)
and in the Replace box, leave it blank
Click Replace All
After the lines containing KEYWORD1 are deleted, press CTRL+A to select all, then go to TextFx -> TextFx Edit -> Delete Blank lines
It's quick and it works, although others may have different methods. I generally use this to clean up my harvested URL lists - even with the best of footprints for some reason I get a shitload of blogspot blogs which need to be eliminated! Peace out!