There are multiple ways to remove product data from your Merchant Center account. It's important to remember that all products expire from your Merchant Center account after 30 days if the product data does not get updated within that timespan.
Remove the products from your product data feed: If you're updating your products via a data feed, simply delete the product(s) from your file and submit the feed again.
Use the expiration_date [expiration_date] attribute: Add an expiration_date [expiration_date] to any products that you would like to remove on a specific date. Learn more about using this attribute in the product data specification
Bear in mind:
There can be a delay of 24–48 hours when a product can still appear in Shopping ads and listings once it has been removed or excluded.