No needed to use sprey for air filter. The Boxers engine R850-1100-1150 have automatic system oil for air filter. You can see that if open the lift, the air filter has little oil.
So clear it (every 5.000 miles) by water and fit it again
Just read the instruction leaflet on my K&N recharger pack and it says the following:
Never use a k & n without oiling (the filter will not stop the dirt without the oil)
Use only k & n formulated air filter oil
K&N air filter oil is a compound of mineral and animal oil blended with special polymers to form a very efficient tack barrier. Red dye is added to show just where you have applied the oil. Eventually the red colour will fade but the oil will remain and filter the air.
Goes on to say Never use:
Automatic transmission fluid.
Motor oil.
Diesel fuel.
Wad 40 or other thin oil.
The tin doesn't specify the actual make up of the oil.
If you only have other air filter oil I wouldn't see there being a real problem - perhaps someone will know that answer.