Do MAQ's affect metal frame runners?
The answer from the MAQS FAQ
Q)
On the product label it states: This product is corrosive. Do not allow
product to contact metal surfaces. Are the strips safe to use with metal
queen excluders?
A)
Formic acid vapours are corrosive to ferrous metals, but not aluminum or
most stainless steels. Some queen excluders get a white powder on them
and will show rust around the edges over time. Plastic excluders are not
affected; there are now some good ones available.
Thorns runners are galvanised steel but I'm not sure how acid vapours and zink work together.