Sculpture is 3-dimensional.
Low relief sculpture is a technique in which the subject of the sculpture is just barely more prominent than the background. High relief sculpture is a technique in which the subject of the sculpture is very raised and extremely prominent against the background.
Relief sculpture
A sculpture should be free standing. If it is not, it may be a relief: relief: sculpture consisting of shapes carved on a surface so as to stand out from the surrounding background
You did not state what the sculpture was made from. This would determine how you clean it.
Regular sculpture is completely in the round, for example a 3-dimensional person or object, whereas a relief sculpture is usually fairly flat, like a picture, but is somewhat sculpted to appear to be coming off or out of the surface
Bas-relief is an art term used to describe a sculpture that has minimal depth to the faces of the human sculpture than they actually have in real life.
a relief sculpture?...
Ninevah
Relief sculpture.
Sculpture
Figures are carved in high relief with deep undercutting.