I bought old car - VW Bora 2001 - and the air ventilation is full of dust, especially when I turn the air heather on I can smell burning dust. 

How can I clean the air vent system besides changing the pollen filter? Is there an easy way of cleaning the air heater and the air pipes?

PS: I am missing appropriate tags, please create and re-tag this post if you want.


Question: Can an untapped creature "become untapped?"
Answer: No. There must be a transition. As per the English definition, "to become untapped" is "to begin to be untapped".

In fact, the ability you mentioned won't even try to untap it. It's impossible untap a permanent that's already untapped. That's why you can't activate an ability with the untap symbol ({Q}) in its cost if the source of the ability is already untapped. 

Similarly, it's impossible to tap a permanent that's already tapped. That's why you can't activate an ability with the tap symbol ({T}) in its cost if the source of the ability is already tapped. 

This wouldn't stop you from casting a spell that would try to do these impossible actions. The spell will simply do as much as possible, and skip over the impossible instruction. e.g. Gerrad&#39;s Command on an untapped creature would effectively become "Target creature gets +3/+3 until end of turn.", and Crippling Chill on tapped creature would effectively become "Target creature doesn't untap during its controller's next untap step."