In order for the BONECO ESP filter to maintain its effectiveness, it must be cleaned from time to time. We recommend a cleaning interval of 2-4 weeks depending on the intensity of use. Contamination is relatively easy to see on the filter. The filter should be cleaned at the latest when the static crackling noise that can be heard when the device is switched on does not disappear even after 5 - 10 minutes. The ESP filter can be cleaned by hand under running water or in a dishwasher.