Try with regex, to replace the match with nothing
This page suggest :
(/\*([^*]|[\r\n]|(\*+([^*/]|[\r\n])))*\*+/)|(//.*)
This is also matching the Javadocs, so you would have to tweak it a bit. There are also other variations that you can try.
Have a look at this other SO question. It is suggesting to use an ANT task that is processing the comments and strip them from the source. In this way you can have a button or keyboard shortcut that is calling the ANT task.
As suggestion put a Label in the history before doing big search and replace so later you can compare if want to restore any comments that may have been stripped.
