Spots "spotting","knifers", "knife hits", "knife tokes","dots", "hot knives", "blades", or "Bladers") are terms referring to a method of smoking cannabis

Cannabis (drug)

Cannabis, also known as marijuana among many other names, refers to any number of preparations of the Cannabis plant intended for use as a psychoactive drug or for medicinal purposes. The English term marijuana comes from the Mexican Spanish word marihuana...

 . In this method, small pieces of cannabis are rolled (or simply torn from a larger bud) to form the "spot". Generally, the tips of two knife blades are heated, the spot is compressed between the two blades, and the subsequent smoke is inhaled. Another means that is gaining popularity is specially made glass presses heated with a propane

Propane

Propane is a three-carbon alkane with the molecular formula , normally a gas, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central...

 or butane

Butane

Butane is a gas with the formula C4H10 that is an alkane with four carbon atoms. The term may refer to any of two structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, butane refers only to the unbranched n-butane isomer; the other one being called "methylpropane" or...

 torch. In order to facilitate this process, a "spottle

Spottle

A spottle is a funnel-shaped object, usually made out of a bottle with the bottom either cut or broken out usually used to inhale marijuana smoke when spotting...

" (also referred to as a "bowser" or "hooter") is often, but not always, used to funnel the smoke and maximize the amount inhaled. A spottle is generally made from a funnel or cone-shaped container, such as the top (or neck) of a plastic or glass bottle or a gallon of milk/water.

Use in different countries

Although practiced the world over, the spots method of cannabis smoking

Cannabis smoking

Cannabis smoking involves inhaling vapors released by heating the flowers and subtending leaves of the Cannabis plants, known as marijuana. Alternatively, the cannabis plant flowers may be finely sifted producing kief, a powder especially rich in the oil-glands or trichomes which contain the...

 is most common in New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

 & Northern Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. Possession of knives that have been previously used for spotting (easily distinguished by their blackened and discoloured appearance) is considered "possession of paraphernalia" and is thus illegal under New Zealand law. If convicted, the accused faces a possible maximum 1-year prison sentence and/or a $500 fine. . In 2008 six New Zealand soldiers were "sent home in disgrace" from their posting in Afghanistan after it was discovered they were spotting hashish . In the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, this method of smoking is relatively rare, and appears to be getting rarer. One 1998 survey of regular UK cannabis users put usage of the "hot knives" technique at only 1.3%, down from 5.2% in 1984.

Health issues

Users spotting cannabis are susceptible to all the associated health risks of other methods of smoking cannabis. Spotting cannabis oil or resin is thought to be particularly harmful to the lungs, as the smoke comes off the oil at such a high temperature. One possible way of minimizing the risks of spotting marijuana is using cooler knives, leading to the tetrahydrocannabinol (THC)

Tetrahydrocannabinol

Tetrahydrocannabinol , also known as delta-9-tetrahydrocannabinol , Δ1-THC , or dronabinol, is the main chemical psychoactive substance found in the cannabis plant. It was first isolated in 1964. In pure form, it is a glassy solid when cold, and becomes viscous and sticky if warmed...

 being vapourised rather than the entire plant matter being burned . Some users also fill the lower half of the spottle with ice (that stays in place by being frozen to the edges of the spottle), but much more common is to just freeze the bottle, this leads to a cooler smoke that is less harsh on the lungs .

Care must be taken not to touch the side of a plastic spottle with a hot knife when inhaling spots, as burning plastic gives off many toxic chemicals, including (in the case of Polyvinyl chloride (PVC)

Polyvinyl chloride

Polyvinyl chloride, commonly abbreviated PVC, is a thermoplastic polymer. It is a vinyl polymer constructed of repeating vinyl groups having one hydrogen replaced by chloride. Polyvinyl chloride is the third most widely produced plastic, after polyethylene and polypropylene. PVC is widely used in...

 plastics) dioxin, a carcinogen

Carcinogen

A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...

. For this reason, many smokers prefer to use a glass bottle.

A 1998 joint submission by the Royal Society and the Academy of Medical Science on the recreational and medical use of marijuana expressed concern about the use and dissemination of the "hot knives" technique. The submission speculated that increasing use of methods of smoking that enable massive inhalation (and therefore higher intake of cannabinoids) may lead to an increase in incidents of short-term cannabis-related mental disturbance.