You actually can do this. If you export a recipe to Excel, you will get a workbook with two tabs. One with the recipe and one with all of your ingredient inventory. Delete the recipe tab all together. On the inventory tab, you can make any changes you want, even delete and start from scratch. Then import back into JC and this will overwrite the inventory with whatever you have in your spreadsheet. Make sure you have a backup file incase it goes bad. It took me several attempts but I finally figured it out. Not perfect but I am very comfortable in excel and using this method is much faster than going
through the inventory editor.
If there's any interest, I can produce a how-to walk through....