Which type of substance is commonly manipulated with push rods?

The substance that is commonly manipulated with push rods is cocaine. This practice typically involves the manipulation of cocaine in its solid form, often seen in the processing stage where push rods can be used to compact and form the substance into a usable product for distribution. Push rods are tools often utilized in the production of crack cocaine, as they allow for the shaping and compacting of the material into specific forms.

In contrast, while heroin and methamphetamine can also be subject to manipulation, the specific association of push rods is most strongly linked to cocaine processing. Alcohol does not typically require manipulation with tools like push rods, as it generally exists in liquid form and is served as such.