A roach is the remains of a joint, blunt or roll up cigarette after most of it has been smoked. Most roaches are disposed of immediately after smoking a joint, however some users will retain the roach for use at a later date. Some users maintain that smoking the roach again has a more intense high due to a high concentration of resin that gathers at the tip of the filter.
Small metal clips to facilitate the smoking of a "roach" are called roach clips. Roach clips cover a wide variety of paraphernalia including alligator clips, forceps, needle nose pliers, ceramic pieces with holes through them, and tweezers.
In Europe, the United Kingdom and most Commonwealth nations, "roach" can also refer to a bit of rolled thin cardboard in one end to serve as a mouthpiece - called a "Roach Tip", "Smoking Tip, "crutch" or "filter" in North America. When this is employed, a joint can still be held securely after it has burnt down to a short length; thus, the entire length of the joint may be smoked without the aid of a roach clip.