I had to clean mine the other day.
The blow out and the draining doesn`t help.
Pull down the hose of the nozzle, than pull upwards out the nozzle. When the nozzle is in your hand you have to pull out the white plug of the bottom of the nozzle. Be very careful at this stage because there is a very small tiny ball inside above the spring! Better if you do that above a clean table/desk. When you dismantled you can clean it.
Max. 5 minutes job.