Brass rubbing is as much a technique as the image it creates. You can make a rubbing of anything hard from a brass plaque to a coin. Manhole covers can reveal intricate geometric patterns. Brass rubbings were popular in medieval times as souvenirs of a pilgrimage, and interest was strong in the Victorian era. Special coloured papers are available, along with gold and silver crayons to produce rubbings worthy of being framed. Rubbings of inscriptions have been used as plot devices in movies, such as "Indiana Jones and the Last Crusade."
Clear the object you want to rub of dust and debris. If the object is small or very lightweight, you may want to secure it so that it will not move while being rubbed.
Place the paper over the object and secure it in place with bits of masking tape. The paper should be thin but strong enough not to tear when rubbed with a wax crayon. Paper towels and newsprint are not suitable. Special brass rubbing paper is available commercially, or you can experiment and find something you like.
Feel for the borders or edges of the object and go over those lightly with the flat side of a crayon.
Slide the flat of the crayon firmly over the object in one direction to bring out the image in detail. Stop rubbing at the marked borders. If the object is large, work in small sections at first and go over the whole thing again at the end until you have an even finish.
Remove the masking tape carefully from your rubbed image.
Frame or display as you wish. Historical rubbings frame well with mats, but geometrics may be more effective unmatted and hung in groups.
Rubbing kits are available commercially. Many churches, cathedrals and other venues offer opportunities to make rubbings of reproductions of historic brasses or other objects to prevent wear and tear on the originals.
If the object you wish to rub is on private property, be sure to obtain permission first or you may be cited for trespassing. Objects on public property are fair game, but the police may ask you what you are doing and why and want to verify that you are doing no damage.