There's openings in the drains of our TT that can pass a tablespoon. Knowing that what will go down the drain will be something which can't be replaced, the task was to find a way to cover them but still let the water flow freely out.
While wandering aimlessly through a Home Depot, I passed through the plumbing section. A card, hanging on a peg board hook, contained exactly what I needed. It's called a "wire mesh drain strainer". Looks like a spaghetti strainer hanging from a big washer. Stick it down the drain and press fit the strainer and top so it fits flat on the top of the opening, doesn't move inside the drain and you've got something which will allow all the water to flow out but will stop your rings, etc. from following behind. About $2 and we bought one for the shower, kitchen and lavatory sink drains.
Picked up extra ones for home and popup drains too. If there's a hole, our stuff will fall into it.
thanks!
what a great idea!