Excel Spreadsheet Bloat

I have had people in the past who have had spreadsheets that seem to “bloat” and the file size gets huge for no reason. I was able at one time to find some information on how to correct this. I think you select all empty cells and the clear contents and re-save the file. However, I cannot seem to find where I got the information. Can anyone verify this or point me in the right direction.

Thanks-