1.Start by clean out any old litter from your litter box.Also, if you can find the kitty litter pads for those expensive litter boxes (they are available at walmart in the cat care litter isle), get the pads and place them in the bottom of your litter box before putting in the litter- it absorbs all wet stuff and keeps the smell down!
Next, replace with your favorite litter and shake down level. (preferable is the odor control for multiple cats even if you only have one. What ever you do, please do not use the cheap 1.00 bag cat litter as it really seems to make the smell worse..I tried this with this method and even tried to use baking soda in it but it still did not help with the smell..
Next, Take Arm & Hammer pet hair and odor remover (which for the carpets but it really works and wont harm your cats) and sprinkle on top of fresh litter…if you want, you can mix it into the litter and then sprinkle some more on top- it seems to help it more if you do..
Now, just make sure to change the litter box (inbetween scooping) usually once every two weeks. This will allow you to keep everything clean and get rid of the musky urine smell that sometimes follows a litter box..
Also, I recommend using gloves and a cheap face mask (also available at walmart in the paint isle) this will help to keep the smell and any bacteria out of your body which can be harmful especially if you have a weakened immune system