Hmm I am not 100% sure if this will work or not but I am 99.99% that it should =], what you can do is make sure all of your files are in one folder then open up anyone of those files, once opened press CTRL+F . This will open up the Find and Replace box. Change your settings to match these
Find In: Change this to folder and then select the path to your folder.
Search: Source Code. (It should be selected by default, but just make sure.)
Find: Place the string(s) of code that you want removed in this box.
Replace: Leave this blank.
Ingore Whitespace: Make sure this is checked.
Once all of these settings are matched, press replace all... This may take a while as you have 500 files.. If you do not mind me asking, what are you making that has 500 files?
Like I said this should work, just make sure you type in the exact line of code that you want though, because this will remove all of the lines of code matching the pattern that you place in the Find box.