If all you need to do is strip such content, you could take a look at the XSSSanitize Java action from the CommunityCommons module. Be sure to read the documentation about the different filter options. These filter options refer to XML files, which you can also edit manually to allow only the characters you want to keep. The documentation can be found locally, once you've imported the module, in /projectfolder/resources/communitycommons/antisamy.