I've done that. Spreadsheets are a brilliant timesaver for sorting, but I find them absolutely agonizing for classifying. I'm using a mouse, a tool I find clumsy even for the uses it's best suited for, for a job that's much better suited for picking up and moving physical objects around, and there isn't enough room on the screen to both show all the piles and make their contents visible.

I should add that to describe that as "virtually the same" sums up what most annoys me about computerization. Some jobs of this kind are so much easier on the computer, it's breath-taking how much work they save. Others I find just get clumsier. Inability by the promoters to grasp my problems with the latter makes their descriptions of their tools and their recommendations for particular ones useless to me. It's frustrating.

A better possibility would be to create a column in the spreadsheet for the categories I perceive, label all the obvious cases, sort the file, consider the remaining problem cases, and so on. But that still has the problem that I can't look at all the piles at once. The unlabeled ones are at this end of the file, the categories extend for pages backwards. I'd rather have piles.