History Log assist you identify individual items, and whether they were transferred. It is also a necessary part of the copy process, so in case you face with any interruption (e.g. due to timeout, memory, network) it can keep track and when you rerun continue from where you had the timeout. It is very important not to delete the history log, until all items are Transferred and Finalized.
There are two ways to filter the data. By the component type, and the result. Remember that an item is considered transferred when it's status is 'Transferred and finalized'
To delete history log based on the filters just filter what you wish and press button 'Delete History'