El Capitan/Snow Leopard 10.6

[ChefClay]

I have a 2009 Mac which ran El Cap. I tried to reset for a new owner to factory settings (no original disc with Mac)
When unable to do so, contacted Apple and was informed that it couldn’t be re-set as the original prog was Snow Leopard 10.6 and I would require a disc with this on.
Bought a Snow Leopard disc and tried this.
Mac showed seven stages of erasing El Cap and I then thought I was okay to load new disc with Snow Leopard

on.
Once again El Ca appeared and I am no further on.
Can anyone assist please?
I just want at the end of the day, to restore the Mac to factory settings!!!!

 

[G4DPII]

You need to start up from the Snow Leopard disk. Insert the DVD and as you turn on the Mac hold down the C key. It will be a little slower to load as it's reading the DVD first.

Then erase El Capitan through the Disk Utilities that load from the Snow Leopard Install disk.

 

[Fishrrman]

OP:
Do you have access to a newer, working Mac?
Or... no?

If you are on a newer Mac, I suggest you download the El Cap installer, then create a bootable USB flash drive version of the installer, and then "wipe and install" on the OLD iMac that way.

Try this link to obtain the full El Cap installer:
https://support.apple.com/en-us/HT206886

You'll need a USB flashdrive (16gb is the best size).
You'll need a little free app called "Boot Buddy".

Initialize the flash drive to HFS+ with journaling enabled, then use Boot Buddy to create the flash drive installer.

Boot from the USB installer, but when you get the install screen, DON'T continue.
Instead, quit the installer, open Disk Utility, and ERASE the internal drive to HFS+ with journaling enabled. NUKE IT.
NOW quite DU and reopen the installer, and do a completely clean install.

When the installer is done, it will present you with the setup screen.
DON'T continue.
Instead, reach around the back and press and hold the power-on button until the screen goes dark and the iMac shuts down.
NOW hand it to the new owner.
It will reboot to the setup screen for him, just like new.