Follow the below steps for tridion cleanup,

1. Go to Content Manager and open the publishing queue.
2. Set the start date to 1st Jan, 2018 in the date section as shown below,

      3. From the user list select the users one by one and click on Show Tasks button to see if any action has been performed by the user since 1st Jan, 2018 till date,

     4. The users whose Publishing queue is empty from period of Jan 2018 until till date can be deleted after getting approval from Gaetan or Derek.