Maintaining Charities in ItsDeductible

I've used ItsDeductible for years.  My charity list is long and many of the charities I haven't contributed to in years.   If I print the Item Donations report, it lists every charity, including those with $0 contributions that year.  My Primary Question: When it is safe to delete charities without risk of losing records? Other questions: I have multiple listings for Salvation Army and Goodwill, based on the town I was living in at the time.  Is it better to make one generic listing to avoid duplications?  Is there a way to print the Item Donations report and filter to only charities with amounts greater than $0?