what should I consider before selling my bitcoin miner

I'm planning to sell my bitcoin miner. Are there any security measures I should take to protect myself before making the sale? I doubt the buyer can access my wallet through it, but I’d love to hear any suggestions or concerns that I might be overlooking.

If the miner is getting it's Internet via a WiFi connection, you should reset that at least. Or have the device reset to factory settings. Otherwise there is no need to do much. If you leave your wallet address in the config, all that could be done is to look into the balance. Make the buyers life easy by resetting it to factory settings, so he gets a fresh device.

that is great advice, thank you!

Any chance you know how to factory reset a futurebit Apollo miner? I don't see anything in settings or a button to push on the miner itself. It's set up using a Linux OS from the factory. Would BleachBit work the same?

From what I read is that you just rewrite the SD-Card, but I don't own that miner. You may be better off looking for a proper user manual. This may help https://bitcointalk.org/index.php?topic=5340015.msg57091052#msg57091052

if you do not understand how to reset it simply configure it to a different pool/address. say solo.ckpool a btc address a pass word if you remove yours and put in the info above they can’t know where you mined