How do you clean regal ware poly perk coffee maker?

Every time you use it, rinse out the inside and the basket until the water runs out clear. Then fill it with water until the bottom 1/4 inch of the basket is immersed. Run it. Whenever it gets a stale taste anyway, get some baking soda (it'll be a lot).

Put about 1/4 inch or a bit less into the basket, fill the pot to right below the max fill line, and run it. Repeat until the water runs out nearly clear (it'll be quite a few times, so you'll need more than one box of soda). Then, to get rid of the baking-soda taste, fill it to above the bottom of the basket with water. Add 1/3 to 1/4 capful of vinegar. Stir it with your finger into the water, put it in the basket, and run it. This will react away the last of the baking soda residue-- don't worry about any white powder that remains. Finally, run it with empty water. It will be nice and fresh. This is quite harmless and can be repeated any time your percolator tastes stale.