Tatar on back teeth

Lilly had her post spay 6 month check yestetday she has a healthy weight heart and everything else fine but she has some Tatar on the back teeth and I need help how to treat this as the vet gave us no ideas how to proceed

Gosh I'm stunned that your vet didn't tell you what to do! If left alone this could turn into an expensive problem requiring teeth cleaning or extraction.

Our Pushy has always had particularly bad teeth, and I wish we'd been a lot more dedicated in looking after them from the start. Our vet told us to brush his teeth everyday. You don't have to do it for long - about 30 seconds is fine, and you don't need a fancy brush or toothpaste. He says to just use an old stocking wrapped around your finger, no toothpaste, and just rub as many teeth as you can reach and go as far back as you can.
Unfortunately Pushy has had a few teeth removed and had a couple of cleanings. They still get bad and I think he's just prone to it.

ETA: there's a product that you add to water that a lot of people use. It makes the water green and is supposed to help with tartar.

Thank you for the help I figured this was the case if not sorted and I believe it was the vet nurse and not the actual vet which explains a lot as she didnt tell me her exact weight even though I asked