Reorganising TRIM often yields redundant or out dated record types. They still need to exist, since there are still records in the system. However, we don’t want our users to create new records using old record types. The answer is to make the old record types inactive. This prevents them from showing up in the New dialog box.
This is done in the properties of the old Record Type, on the ‘Active’ tab. Set the “Active To” field to the date you want your users to stop creating those records.