This is different for 3ln, as the 2kr had a tank cover. But most things will be similar. Remove tank (you can just unhook all the bolts and 'twist' the tank out of the way rather than unhooking all tubes from it). Your air filter will be in a plastic casing. Remove the top. Inside you will see the filter - pull it out. Cleaning - you can clean them to a certain degree. I have used vacuums on them, high pressure air hoses, and also just water (with adequate time to dry after) if they are not paper based. Replace - buy a new one and put in instead.
