Re-distributing (Recycling) Modded Phones

[Guest CoopsAtWork]

Hi all,

We like to recycle things and we also like to do it if there is a little money involved.

So if I were a Recycling organisation, I would be very happy to pay a little money for a used phone, ensure it is wiped and then sell it on.

I would wipe (that is, master reset) the phone to ensure that the previous owner is protected, by removing all personal data, apps etc.

Here's the question - and please don't be offended by what I'm about to say: I'm not informed enough other than to ask it in very bald terms; apologies in advance.

If passing on a modded phone in this way, is it possible that I could be passing on malware to the next recipient?

And, what steps could I take to ensure the recipient is protected?

I'd really appreciate your comments - thanks.