note: there are new, ‘magical’ cleanup functions that may solve these issues for you much easier… please see:
Find Manufacturer’s Logos & Combine Duplicate Manufacturer in the Shopping Cart Cleanup tools section.
Remove redundant manufacturers with the Inline Product Editor
Step 1. First, make sure you can see everything you need: “Add” the Mfg column to the View, and increase the number of visible products to 200.
Step 2. In the filter box under MFG, search for the “Bad” manufacturer name. If you type “Intl” into the filter, only the “Intl Playthings” items will come up, and you’ll be able to assign them all to “International Playthings.”
Step 3. Check top checkbox to select all. Selected products turn blue. You can also hand-select multiple products by clicking their individual checkboxes.
Step 4. Change one item to the “real” mfg name. Click the manufacturer’s name in the Mfg column to bring up the dropdown of all the manufacturers on your site. Scroll down to choose the right one. The entire column will turn orange to let you know that they’re ALL being edited.
Step 5. Check your work
Remove “INTL” from the filter and hit return. Type “INTL” back in. Nothing should show. If there are left-overs, simply repeat the reassignment.
Look in the front end for that brand. Does it have any products associated with it? Does the “Real” manufacturer have all the transferred products?
Step 6. Delete the bad manufacturer name
If it has products assigned to it, you won’t be able to delete it.