Copying a column out of a report rarely gives you just that column. Row numbers, totals, pagination controls and stray metrics come along, and they all look like data until something downstream chokes on them.
Removing the obvious noise
Filtering out purely numeric lines clears most of it in one pass, without touching the keywords and URLs that contain numbers legitimately.
Why it matters more than it seems
A keyword list containing 1, 2, 3 and 847 will happily be submitted to a research tool, which returns volume data for those "terms". Nobody notices until a report contains rows that mean nothing.
Check the count afterwards
If the filter removes far more than expected, the paste captured a whole numeric column rather than a few stray values — which usually means it is worth redoing the copy rather than cleaning up after it.
Try it: Remove Lines That Are Only Numbers on SeoWolf's Notepad.