Items like that are referred to as leeches. You can do a forum search and read around for tips in previous topics on that subject.
You can also install the Self-Study Quiz script, plus the Additional filters. Then you can put together review quizzes (that don’t affect WKs SRS) of just leeches that you have accumulated.
You can also look through the list of API and third party stuff that’s aimed at quashing leeches.