I stopped buying play doh 4 years ago, in favor of homemade no-cook doh. Mostly because of how expensive those little canisters are relative to how quickly kids mix the rainbow colors to greige and leave it to turn into sharp little crumbles on the ground. My son(not coincidentally 4 years old) found an ancient tiny canister of yellow play doh and was fascinated by the bright color and smooth (if rubbery with age) consistency. He asked for more, which inspired me to try the cooked play doh recipe on Tinkerlab. We had a weavil-infested bag of flour in the freezer for just such a purpose, and I buy salt and cream of tartar in bulk at The Berkeley Bowl for similar reasons!
Then we stirred and stirred and stirred, and once it broke my old wooden spoon in half(seriously) I knew it was probably the right consistency, and plopped it onto a sheet of waxed paper for kneading.
I divided it into four balls and kneaded in food coloring and a drop of lavender essential oil for yummy smell(which I wouldn’t do if my kids hadn’t encountered it before, or if they were doing the initial knead, as undiluted it can be a skin irritant!)