How can I get rid off foreign object from my iMac's DVD/CD drive?

Shut down and unplug the iMac.

Cut a hook out of a thin piece of plastic or ridge cardboard.

Have someone hold the iMac on it's side with slot facing down and probe the slot with the hook.

FWIW this is the preferred way to remove an SD card from the DVD/CD slot.

So I'm guessing that it will also work to remover the canned air straw as well.

Among other techniques, a powerful vacuum or a piece of bent card stock have been known to successfully remove objects stuck in the optical drive.

Camera Card in CD port... HELP!!! - Apple Community

Ella,

None! Considering the advanced age of the computer if you don't want to spend money fixing it then you can replace the DVD drive with an external one. I'd recommend visiting MacSales.com, they have many to select from in all price ranges. I recall seeing some as low as $25. Remember to assess your needs and select one that fills those needs.

Good luck!

It is not a technique I used personally. In one of them I specifically advised against it:

I would not recommend fishing around in there with anything. You could easily break the optical drive mechanism.

You would need to read those older, archived Discussions (click the blue text). One of them is 19 pages long. If Apple still used optical drives in their products those 15+ year old Discussions would now be hundreds of pages long.

Well, like I indicated before, the optical drive is not working at all.

Depending on drive model, not working could affect removal of a foreign object. On some iMacs of that vintage, the optical drive has a failsafe mechanism. If the drive fails, a mechanical "fence" deploys to block further insertion of disks that would be damaged if piled up in the drive.

If your drive failed and is a model with that fail-safe fence, that will make getting the object out by gravity on hooking more difficult. You can tell if the fence is deployed because you cannot insert a disk; the block is usually visible if you shine a light tinthe slot. If there is no fence, post back.

suppose you could follow one of the ifixit guides to open up the imac enough for you to disconnect the power cable from the internal optical drive then it would no longer go bump in the night