Deleting computers

If you are removing multiple computers at once, the easiest way that I've found is to do an inventory search (advanced if needed), then once you have your results, look to the bottom of the page and select "Delete Computers" from the "Take Action on Results" form.

Note: This will delete all returned results.

I would suggest having a couple of Smart Groups or Advanced Searches setup as msblake suggested. Typically you can base retired machines from your environment by there last check in time to the JSS or if you associate a Department/Building to retired machines. You can just create a Advanced Search or Smart group then from those criteria. Below is an example of what you could do for a Computer Smart Group for computers that are not checking in to your JSS.

Log into the JSS>>Management>>Smart Computer Group or Smart Mobile Device Group>>Create>>Select Computer Information or Mobile Device Details>>Select Last Contact Time for OSX and Last Inventory update for iOS>>Select the drop down and choose More than X days ago and enter in the number of days you would like.

Do you notice any performance issues on the JSS when deleting? We have seen deleting computers really bog down the JSS for other users.

If you are seeing your JSS bog down when deleting computers I would suggest checking your memory allocated to Tomcat. JSS>>Settings>>Database/Web Application Health>>Web App Memory>> Here I would check what you have set for Max Memory.