motoroil and filter oil is nowhere near the same thing... sure you can use 10w30 on your airfilter, I know you wanted to buy that new stroker crank and top end anyways.....
Actually, in some places it looks oddly clean. Make sure you cover all surfaces (inside and out) with oil and squeeze/knead it to evenly distribute. Then squeeze out any excess....like the oil filter oil instructions say.
Large ziplock bag, put the filter in, poor oil in, seal and squeeze.. Do not worry about overoiling it, that cant be done.. to clean, sink full of hot water and dawn dish soap. repeat a couple times. then rinse completely. dont forget to grease the lip.