The steps are as follows:-
Step 1. Go to catalog and then select catalog manger in the dashboard.
Step 2. In that go to export and select store and select attribute delete option. In this we have selected Spykar as our store and then click on export button
Step 3. After clicking on export button this excel file will be downloaded as shown here. Now among all these product id we will see whose attribute are wrong and which among them has to be deleted. We will keep those product id in that sheet only and will delete rest all correct product id.
Step 4. As you can see in the previous image the data sheet had all the product id here you can see only those product id are which has some discrepancies. Save this sheet in csv format.
Step 5. After saving the sheet for selected product id in csv formal import that sheet after selecting the brand and import type and click on choose file
Step 6. Choose file or you can also drag drop the selected file. Then click on import.