Hi Lukas,

Yes you're right to question the effectiveness of the standard air filter. It is as you say just layers of wire mesh. When my Judson was restored by Alejandro Martin (almar9@hotmail.com) he introduced a layer of air-filter material between the wire mesh. It a porous material that will allow a good airflow whilst providing a medium to absorb and retain oil.

I have Googled "air filter material" and it returns a lot of hits but I'm not sure who would supply it in small size so that is something you might have to research.

Hope that gives you a lead.