Class 4 primarily contains industrial oils, greases, wax and lubricants, as well as fuels and illuminating substances. It should be noted, however, that machines, apparatus and lamps that use Class 4 fuels and illuminants are not in Class 4. For example, lamps for lighting are in Cl. 11, regardless of whether they are lamps powered by electricity or by a Class 4 fuel.
Candles and wicks for lighting are in Class 4, even if they are scented. This may seem inconsistent since other items for lighting are in Cl. 11, and scents and perfumes are in Cl. 3. However, candles are neither apparatus for lighting nor perfumes; they are considered to be illuminants and, in fact, are made of the illuminant that makes them work, namely, wax. It should be noted that, when candles are considered to have a specific function, they may be classified in other classes, such as massage candles for cosmetic purposes in Cl. 3 or massage candles for therapeutic purposes in Cl. 5. Furthermore, certain wicks that are intended for use with a specific apparatus can belong to the same Class as that apparatus, for example, wicks adapted for oil stoves in Cl. 11 and wicks adapted for cigarette lighters in Cl. 34.
Amongst the fuels included in Class 4, there are certain hydrocarbons which may be classified in Cl. 1 when used for chemical purposes and in Class 4 when used as a fuel, for example, benzene is in Cl. 1 while benzene fuel is in Class 4.
Finally, this class includes dust absorbing, wetting and binding compositions. These compositions are used, for example, in sweeping roads or in building construction to prevent dust from floating in the air. They can also be used to absorb, and thus prevent, chemical spills from spreading and damaging the environment. They are included in Class 4 because they are usually oil- or grease-based products.