A shirt may be the first resource when wiping lenses but don't do it. It may get rid of the smudge but it will cause damage to the lenses that can't be erased. Also do not clean your lenses too often or you will risk scratching or damaging your lenses.
To properly maintain you glasses you want to, first, make sure that you keep your fingerprints off them. Secondly, wipe the nose bridge and nose pads last because that is where the most residue is and you don’t want that getting on the lenses.
No matter how much you try to avoid it your glasses are going to get dirty. This, in turn, can affect your visibility which can affect your safety and ability to work. Lens cleaners are perfect for keeping this from happening and help you retain clean, visible glasses.