To make it easier to apply a wipe-on finish, I purchased a wash bottle from a nearby Walmart. When it comes time to finish a piece, just dispense a small amount of your finish into the bottle. A squeeze bottle like this makes it easy to control the amount of finish, applying just enough without making a mess. A cotton rag helps apply the finish to your workpiece, and nitrile gloves keep your hands clean as well.
This handy tip isn’t limited to just the wash bottle shown in the top photo. Empty ketchup and mustard bottles work just as well.