With newer (experimental) clients 4.2x you can abort individual Results. With 4.19 clients there is no other way than to reset the project.
The somewhat hard way may work, at least it shouldn't go worse than resetting the project: stop the client and delete the slots directory (in the BOINC directory), then start it again. Unlike resetting the project this shouldn't cause another 11MB download.
BM

Obsolete work units
)
I wonder if the problem is the following. Einstein@Home estimates the CPU time needed to finish SCIENCE part of the application, but doesn't take into account the time taken to run the screensaver. Perhaps what is going on here is that the graphics thread is consuming more CPU time than the science thread.
Could people who have been getting too many WU report what fraction of the CPU time is going into graphics and what fraction into the science thread? This can be determined by running the task manager to watch total CPU time, and watching the BOINC manager to see the reported science thread time for the same period.
Bruce