Can you over oil an air filter??

I use oil that has a dye in it so I can tell when the foam is completely oiled. I use as little as possible to acheive this.

you said you used a half bottle of oil, did you squeeze out the excess oild before re-installing it??

What I do is get a big clean plastic bag,put your filter in it . Pour a lot of filter oil into the bag onto the filter , squeeze it around making sure the filter is completely saturated. Carefully cut a small corner of the bag so it acts like a funnel, squeeze the bag and filter to get as much oil back into the bottle. Open the bag up and get the filter into its original shape but leave it in the bag for a few.

While the solvents are evaporating from your filter oil is a good time to check your tires ,spokes ,rims, break pad thickness, and adjust your chain and lube . Clean hands put on those latex doctor gloves , grab the filter, mop up the little bit of the excess oil that is still in the bag with it and install.

Gallon size Ziplock bags work great and scissors are best to cut the small corner funnel. For some reason it just doesn't work as well trying to close the ziplock back almost all the way and using that as the funnel.

I use a sport gatorade bottle (the one with a cap), I pour my filer oil in the sport bottle.

Then it's easy to put it evenly on the air filter massaging it so it will gets everywhere. No spill, No waste and a perfectly oiled filter.