Adding and removing variations to active ebay listings

Hello. I have three ebay accounts with thousands of listings on each account. I currently sell phone cases, so each listing has approx 100 to 200 phone model variations. I have recently bought new phone models and want to add these new phone models as variations to all active listings to increase sales. Firstly I want to remove old phone model variations, so I can provide a list of old models (around 30 models) to initially be removed from active listings to clear up listing space. Then I can provide a list of new phone models to be added as variations in order to all active listings for example new iPhone models added under all iPhone variations and so on with other brands. We can start with the smallest eBay account first then work our way up to the largest eBay account which has approx 10,000 listings.