When teaching the Basic Depreciation class, offered through Sage U, I recommend to students that they create a database file for testing or redundancy purposes.  You could even name it "Test," or "Sandbox" if you prefer.

Then, copy your active company onto the test database, and voila!  You've just created a sandbox to work in.

Unless you're using the Premier Depreciation program, there are a number of ways to create a new database.  Many use the Data List Manager. 

After you create it, use the Copy Company feature to copy your active company onto the new database file.

How do I create a copy of my live database to use as a Test database?