You can clean a K&N air filter without the kit by taking these steps:

High-performance air filters like the ones manufactured by K&N are meant to be reusable.

But this means that you will have to take the time to clean it regularly.

Fill a sink basin or wash tub with warm, soapy water

Fill your kitchen sink or a tub with warm water. You'll want some suds to help remove the dirt and grime, so add just a bit of dish soap. Set the air filter inside as soon as the water is nice and soapy.

Let the K&N air filter soak in the water for five minutes

You'll want to let the filter sit in the warm, soapy water for around five minutes. This will give the solution time to go to work on all the filth that the K&N air filter has spared your engine from receiving.

Remove the filter and let it sit for an additional five minutes

After five minutes, remove the air filter from the soapy water and let it sit on a clean cloth. This gives the filter additional time for the soap to work away at the dirt.

Gently rinse the soapy solution from the filter

Now it will be time to rinse the soapy water and the remaining grime off the K&N air filter. This should be done very gently. The water from your tap will work. Just make sure that it is pretty warm. Let the stream of water remove all traces of soap.

Gently rinse the soapy solution from the filter

You won't want to reinstall the K&N air filter while it's still wet. Place the now-clean air filter on a cloth or towel and let it air dry. As soon as there isn't any trace of moisture left, you'll be almost ready to pop it back into place under the hood.