Correct! I have been selling K&N filters for almost 15 years and seen some people do some really retarded stuff to them. The holes in the cotton are of a certain size as to facilitate the use of the oil that is designed for it that closes the holes in the filter down to the correct micron size. If you clean it with the wrong stuff you will damage the element. If you use the wrong oil it will not function correctly. DO IT RIGHT! Buy the filtercharger kit and READ THE DIRECTIONS!