If you have products you no longer sell, you'll need to obsolete them from both Xero and the CRM. Xero has an idea logged to enhance this process - vote on this idea here.
You'll need a Xero account and login
Step 1: Find Product to Delete
Within Xero, navigate to the product you no longer want to sell on the CRM.
Step 2: Making the Product Obsolete
Once you're on the product in Xero, check the product is active and click 'Edit Item'.
Finally, untick 'I sell this item'.
Step 3: Check CRM has Updated
You may have to wait approx. 15 minutes for these changes to appear in the CRM, but once this has been imported, you can see the product marked as obsolete and no longer sellable.