This is true Paul, I was actually typing this while having breakie at the beach. As you know, this is the time of year that many Scandinavians are enjoying the sea, sun & sand or 3 S’s, maybe this is why vacuum cleaner bag popped into the bowl of porridge that was my brain at that particular time, this is my excuse and I’m sticking to it 😆
I’ve just had to install a vent in my kitchen, new law for gas ranges, so we can’t end it all and accidentally take the block out with us 
The vent they put in has a fine mesh filter, steel, it’s quite thin and serviceable, more like the sponge filter you see in the rear of heaters, but metal, maybe I could cut one up? 💡