The first thing that you need to do is to make a list of things that you had borrowed from your ex. Locate them all down and put them in a box. You cannot ask to have your stuff returned unless you are in a position to return your ex’s stuff. If you have lost something or broken something that was borrowed, it is best to replace it with a new one.
Next, make a list of the stuff that your ex borrowed from you. These may include DVDs, CDs, some jacket that you may have lent her/him in a cold weather, a shirt with your signature perfume/cologne on it, etc. Read through the list a number of times to make sure that you have not listed something that may already have been returned to you. Asking your ex to return something that they have returned weeks or months ago can make leave you feeling really awkward and embarrassed.
Once the list is created and checked thrice at least, start thinking about how you will contact your ex to set up the exchange. You will have a number of options in front of you, such as giving them a call, sending them an e-mail, sending them a message on Facebook if they have not blocked you already, getting a common friend to help you out, or simply talk to them in person. The last option is not recommended if the breakup was a really nasty one, as an encounter between you and your ex may result in yet another war of words and maybe a slap or two.
Once the exchange is set up, prepare yourself for it. Check the box that you will be returning. Take a shower and dress up really nicely. You do not want your ex to get an impression that the breakup has left you miserable.
Get to the exchange point on time. Be sure to let your ex know that you are in a hurry. This will surely make them think that you are doing really good and maybe replaced them with someone already. Take your stuff from them and walk away casually. Do not forget to smile politely and say thanks.