Most drug users have heard of sniffing or huffing paint, but very few have resorted to it. Here is some information on how people use paint to get high, but please remember that this should not be done under any circumstance.
Paints that are used to obtain a high
First off lets exclude that bucket paint is used to get high with. The paint that is used to huff or sniff is actually spray paint. But not just any spray paint, here's the two main chemicals that are sought for to produce such a euphoric high...
- Toluene (This chemical is most notably abused)
Heres what Wikipedia has to say about Toluene, Xylene however has no information listed in terms of abuse, except for that it may be used as an inhalant.
Toluene should not be inhaled due to its health effects. Low to moderate levels can cause tiredness, confusion, weakness, drunken-type actions, memory loss, nausea, loss of appetite, and hearing and color vision loss. These symptoms usually disappear when exposure is stopped. Inhaling high levels of toluene in a short time may cause light-handedness, nausea, or sleepiness. It can also cause unconsciousness, and even death. 
Xylenes are not highly toxic as indicated by the high values of the LD50 which range from 200 to 4000 mg/kg for animals. 
Remember that some spray paints may contain other nasty chemicals, always look on the back of the can and read the ingredients. Gases like propane and butane just take more oxygen out of your lungs, just making things more dangerous (even though some people abuse butane itself). Here are some adverse effects of specific chemicals:
- Methylene chloride, after being metabolized, can cause carbon monoxide poisoning
- Ingestion of alkyl nitrites can cause methemoglobinemia, although inhalation does not
- Carbon tetra-chloride can cause significant damage to multiple systems, but its association with liver damage is so strong that it is used in animal models to induce liver injury
- Use of butane and propane can create a risk of burns.
- Benzene causes cancer and other illnesses. Benzene is a notorious cause of bone marrow failure.
- Toluene can damage myelin (CNS damage)  
- NEVER COMBINE ALCOHOL WITH XYLENE OR INHALANTS PERIOD... 
Different colors of paint usually produce a slightly different highs. For example white paint may give you a more intense buzz than black paint. Or at least it seems that way for most people, in most cases, brighter colors (such as green, red, or white) produce a better or more intense high. But everything written here is hearsay of course.
Lots inhalant abusers claim that metallic paints are the best to abuse, and produce the greatest high. Some swear by it, but many metallic paints contain Benzene, and cancer is horrible, so is bone marrow loss. That's why you should always read the back of the can. If you can find a metallic paint without Benzene, then good for you.
Your best shot is to find a can of spray paint with only Toluene and Xylene, chances are it contains a propellant, but you can reduce some risks by doing so. There are many spray paints that contain only these two chemicals as listed ingredients.
Methods of consumption
There are two methods of consumption with two routes of administration (oral or trans-nasal), in terms of spray paint inhalation:
- Huffing: the user will spray the contents of the can into a rag (socks work much better) and inhale the aerosol out of the rag (or sock).
- Bagging: the user will spray the contents of the can into a bag and breathe in and out.
Take a bag of fresh socks (you can find a bag of cheap socks for as low as $1-$3) and simply fold it in half, then spray the paint through the sock and suck the tasty colorful aerosol goodness from out the sock. Remember it may get messy, paint can drip on your clothes, and you may even get paint on your mouth or face (don't freak out, its likely to happen). The more you huff, the better you learn to control it. Some may disagree with this method and prefer bagging instead, as it may be a bit more efficient, and probably less messy.
These effects listed here are in terms of recreational outcome
- A feeling of fullness in the head (thoughts merging into one)
- Intense intoxication (similar to effects of alcohol)
- A form of slight hallucinations associated with intoxication (something minor such as grass looking like fuzz or trees looking funny, hearing a noise)
- Appreciation for surroundings or the world
- Intense dissociation
- Sleepiness after use, can become a long-term effect with increased use
- Craving for taste of paint (usually is associated with habitual use)
- A form of the "wah-wahs" and a suppression of noise (things seem quiet) positive when sought
- Increased suicidal behavior or thoughts associated with comedown and/or habitual use
- Agitation during comedown or shortly after use
- Getting paint on face or clothes
- Becoming emotionally and mentally disconnected from friends or family as a result of abuse (leads to suicidal behaviors or thoughts, something along the lines of depersonalization, possibly worse)
Remember, the effects of inhaling Toluene and Xylene from spray paint will be different than that of something like Diethyl Ether which sure as hell ain't like Nitrous Oxide. Anyone who thinks inhalants get you high due to the gasses depriving the oxygen to your brain, is a complete fuckwad and there is a good chance that he/she has some form of mental retardation. Someone who believes this should squat head beetween knees, breathe in and out as hard and fast as possible for 20 seconds, stand up, and then blow on their thumb. So they may experience oxygen deprivation. Then huff paint, and realize how much of a incompetent piece of shit they were for assuming such a thing. Of course inhalants deprive some oxygen to your brain, but that has no effect on the high that is produced.
Words of wisdom
- The best mentality to have before inhaling spray paint is that you will be experiencing a trip. It should be prepared for and treated as a trip, but it is often carelessly abused. A trip sitter would be good, but is probably hard to find, because hopefully everyone you know of wouldn't approve of you huffing paint.
- Someone who has never had experience with an inhalant SHOULD NOT abuse spray paint as they wont have any idea of what to expect, they should try a less volatile substance like Duster. It is true that there is always a risk of death associated with the abuse of an inhalant at any time. But a first time user should be cautious, they should take small "tester" hits, breathe a lot of oxygen, and avoid inhaling the whole can their first time. A first time user may get carried away, and end up sucking down a whole can of paint. Unsure of how their body reacted to it in the first place.
- It is important to note that when people don't have any drugs they typically resort to another substance that is more accessible or cheap. Someone shouldn't resort to huffing paint because they are out of weed. Though it would make sense for a habitual crack cocaine smoker to resort to this sort of thing. Keep in mind that spray paints should not be used as a substance to resort to, even though it almost always is.
Addiction and habitual use
No one except an inhalant abuser of paint sprays can tell you that it is very addicting. Do not inhale neither Toluene, Xylene, or any inhalant substance for that matter. On a frequent or daily basis, as it will ruin your mind, body, and spiritual well being. Along with relationships of friend's and family, you will most likely become suicidal.