Use the finest drywall screen - it is awesome on rings in the toilet and on calcified pool tiles.  It removes calcium without scratching.  Note:  Use with care on glass. I save my super worn out screens for areas like glass and around faucets.  

For an awesome air freshener, mix a cap full of Downey, or your favorite fabric softener, in a spray bottle with water.  Makes the air smell good and is safe on fabrics!

Put baking soda in cat box to help eliminate odors.  You can also shake baking soda on carpet, prior to vacuuming, to help remove pet hair and odor.