You could use a wrench, or socket. It doesn't take much to get them loose.

If the metal post starts turning inside the plastic post, you will need a second tool to grab the metal post. Unless you are ok with removing the whole post assembly.

A thin crescent wrench (spanner) works. Sounds like you were referring to this tool (which is available at pinballresource for $4). Needle nose pliers might also work if it is not on too tight.
0950C1C2-1E8A-4EE5-B06B-EFD33F598AF8 (resized).png

its basically just a divot repair tool used when golfing

pair of needlenose usually work, on both ends, no special tools needed. then throw those metal nuts in the trash. nothing but junk and a hassle.
get the plastic ones.

Buy a cheap 1/4 wrench and grind it a little thinner on a bench grinder. That's what I use. Works great

push down and turn counterclockwise , you should also change the rubber , it looks original and is cracked and yellowed

Where are you located?

where exactly ? you might be able to have stuff shipped from Player one

i think this is what you need https://www.titanpinball.com/kits/index.php/view/id/151 , it gives you what sizes your game has and how many ,

let me see if i have enough of the rubbers to put this kit together , i can save you on shipping , canada post has free shipping on tuesday in oct for small bus accounts which is what i have , give me a few days , mike

I would not use titan rings.
Use original white rubber.

yes that's what i would use white reg. rubbers , i just sent the titan post just for sizing

I know this is old post now, but I bought a rubber kit for mine at Marco. I also bought a buncha white barrel caps to replace the metal acorns. I think it makes the machine look brighter and cleaner and I never liked the feel of those caps tightening and loosening and you won’t need something to hold the post if the metal cap gets stuck. They’ll probably dry up and need to be replaced eventually but should be fine for many years. I kept the originals all in a bag for the diehards that want original parts if I ever sell it (not!). I also needed to replace a few screw posts in the process so good to order some of those too. If you’re ordering parts get yourself a new shooter rod spring too... highest tension (“red” one).