I have a sheet with heaps of cells with the content
'3
'5
'2
...

The cells are displayed with a small green triangle in the upper left corner.

First: What does this format mean and what is it used for?

Second: To search and replace using ~' does not work for this particular case.

How can I get rid of all the ' in the cells and replace them with an empty space to make the cells in to numbers?

There are heaps of referlas to ~ for search of non character strings,
e.g. http://www.excelforum.com/showthread...hlight=replace
but I can not find anything about this.