Review on Revitalize Your Cabin Air Filter with K&N's Cleaning Kit: Sprayer Bottle Cleaner & Refresher Kit; Enhance Filter Performance; Service Kit-99-6000, 99-6000AMZ by Matt Welch

I am new to K&N and have had my intake system installed for two years and figured every 50k or 100k would be perfect. Well I've noticed that my truck has been losing power over the last few months and as a result I've found that when my filter is no longer red it needs to be cleaned. God I felt stupid but I cleaned it last night, be aware I had to do 2 cleaning cycles due to excessive build up. I oiled it after letting it dry for 8 hours and just applied it this morning. WOW! My trucks are breathing again and I can feel the difference! So thankful that this thing! After that, the oil that comes with these kits contains a dye that will restore the color when you oil the filter. I inserted my photo. The upper left corner is my filter before cleaning, just understand.