When I prefix a number in a CSV with a single quote, the single quote appears
in the cell. If I then select the cell, put my cursor in the edit bar and
hit tab, it'll reinterpret the quote and treat the cell as text.

Is there any way to write a macro that visits each cell and does this? (No,
recording this into a macro does no good.)

This seems to be a common problem- and no, treating it as a txt file and
specifying all the formats is not a decent solution. I could write a perl
script to do this (or presumably a Basic script), but that seems like a lot
of work for a simple problem.