MarKee do you have those filters in your Beaverton store?
CBrown.tx...as far as cleaning: weekly I spray them with simple green let them set for 10-15 minutes; then I rinse them under the sink with hot water (I use the sprayer) and lastly I take them outside and use the garden house with a straight stream.
Monthly I just put them in the dishwasher I use Cascade dishwasher detergent. You can, also, let them soak in a mixture of TSP and water, you can find the ratios on line...I think it's 1 cup to 5 gallons of water??
Which takes me back to my original question "how do I know when to replace them" :-)