Select the range to fix
Edit|Replace
what: ctrl-j
with: (leave blank) (or maybe a space character????)
replace all

Jules wrote:

I've received a large spreadsheet where someone hase insterted manual line
breaks in tons of cells, and I want to get rid of them. I've been going in
each cell by hand to delete the manual line breaks. Is there a way to do
this for a range of cells all at once?

--

Dave Peterson