Be careful when erasing data from your Android phone. It might stick around.

Take caution before giving away an old smart phone. Some of your personal data could still be swimming around on it. 

A new report published Wednesday by antivirus security vendor Avast says it's possible to recover data from Android devices even after users have supposedly wiped them clean. This data includes personal information, such as photos and text-message conversations. 

"Although at first glance the phones appeared thoroughly erased, we were able to recover a lot of private data," the report states. "In most cases, we got to the low level analysis, which helped us recover SMS and chat messages." 

The report describes how most people, when they want to delete their data, will use the standard erase features that come with their devices. "After it’s done, they consider the unwanted data to be gone forever," the report states. However, the report says, that's not true. 

According to CNET, Avast conducted the study with 20 Android smart phones bought from eBay. Then, using a series of readily available digital forensics tools, the security firm conducted three main types of analysis on the phones to dig for data: "Mass storage mount; Logical analysis; and Low level analysis." 

This analysis yielded more than "40,000 photos ... along with 750 emails and text messages, 250 contacts, the identities of four phones' previous owners, and one completed loan application," CNET notes. 

What this means is that while people may believe they are removing all of their data, they are only removing data at the surface level or "application layer," as Avast mobile division president Jude McColgan tells CNET. 

As Time points out, Avast likely wants users to purchase its security software to more thoroughly erase a device's data. But as both Time and CNET have noted, Android devices already have easy-to-use encryption tools on their devices. With the "Encrypt phone" option under Settings on Android phones, users can better protect data that might be vulnerable once the device falls into different hands, Time notes. 

This comes at a time of heightened privacy concerns over personal technological devices. In a 9-0 ruling, the US Supreme Court recently said that police must obtain a warrant before searching the contents of someone's phone. 

That decision stated that cellphones are more than mere consumer devices. As Chief Justice John Roberts wrote for the court, "With all they contain and all they may reveal, they hold for many Americans the 'privacies of life.' "