There is a nifty feature on the Retail side which will perform a clean up for some of the global data to get the Channel DB lean. This is especially important in cases where the POS itself acts as an RSSU and you would look at every opportunity to get the irrelevant data in the Channel DB to disappear(purged).
The feature is available in the Retail scheduler parameters form under the Post database sync, make sure to enable the field Clean up irrelevant master data as True.
What it essentially does is it would execute a stored procedure on the Channel DB everytime Async client has Applied the download sessions. The entities involved that would be cleared are Customers, Employees, Product, Loyalty and Address. The Products and Customers would ideally be already handled from Assortments and Customer address book respectively. There is a possibility of issues arising if you are using Loyalty and in those cases it is better to disable this feature. Please do use the features with caution incase some complicated joins used by CRT may not work due to missing data.