Forgotten iPhone passcode

I have an old iPhone - 6s Plus, I think.

I am trying to reset it to factory so I can recycle it.

Unfortunately, my son - whose phone it was - doesn’t remember the 6 digit passcode.

I have tried the Apple instructions to reset, without success. Has anyone had any success trying to reset?

Those instructions are correct for restoring the phone. I will assume you tried the iPhone 6s and older steps first. Have you tried the iPhone 7 steps yet?

Once you get the the “Connect to iTunes” screen you should be good to go for connecting to a computer. Older systems use iTunes and newer systems require to open Finder and select the iPhone under Devices in the left hand column.

Please let us know how far you get.