If you’re the type of person who likes changing your Android phone every few months or so, chances are you’ve sold your gadget through eBay, Craiglist, or some other secondhand online stores. Before selling it, of course you tried to wipe all your data by restoring factory settings and deleting all files on the phone and memory card. But according to avast!, not all your information is completely and securely erased. They conducted a study that showed not all personal information disappears and it is scary if it will fall into the wrong hands.

According to their experiment, they bought 20 random used Android phones off eBay. They were able to retrieve 40,000 stored photos (including those that they probably wouldn’t want anyone else to see), 1,000 google searches, 750 emails and text messages, four identities of previous owners and even one loan application, among other things. All the previous owners thought they had completely wiped these data off their phones, but with the use of recovery software, avast! was able to retrieve all of these (and more!)

It is very important that you understand that all the seemingly unimportant data you have on your phone can be used against you if it falls into idle and malicious hands. The more “resourceful” the hackers are, the more damage they can do. Just by being able to read your messages and contacts, researching you on your different social media profiles or looking through your pictures, they can piece together your entire profile. They can steal your identity, make transactions without your knowledge and just create havoc in your life in general. Some have even sold personal profiles online to those who need different identities, and maybe even to your rivals and enemies (they can also find out who those are if they’re good).

There are several apps that you can use to ensure that you fully wipe your devices before giving them to other people or selling it online. There’s Full Wipe and Secure Wipe and Avast! also has its own Anti-Theft app which can be downloaded for free from the Google Play Store. All you have to do is install it on your gadget, create a my.avast account, configure the app to your account and then choose the “thorough wipe” option that can be found within the app. Then on your PC, log in to your account and then proceed to delete and overwrite all of your important and personal information from your phone.