There are five primary approaches to making hashish, or making hash oil, or related concentrated products of medical marijuana.

Anyone who attempts to make hash, or make hashish, or make hash oil should know up front that the end product can often be quite sticky. Some products have about the consistency and stickiness of road asphalt. If the process of making hash or making hash oil produces a mess, then plain old drug store rubbing alcohol will do a good job in cleaning up.

The active ingredients in marijuana dissolve in alcohol and other solvents, such as butane. You can make hashish and hashish oil by soaking marijuana in alcohol, or by running butane through it.

The simplest of these methods involves just soaking the marijuana in alcohol for a period of time. The active ingredient will be dissolved in the alcohol. Once the alcohol evaporates off, the result is a rather sticky hashish.

Another method is to force butane through the marijuana and collect the outflow. There are simple methods to do this that are described elsewhere. 

It should be noted that the use of solvents to make hash or make hash oil can be extremely hazardous if not used properly. Alcohol is highly flammable and butane can be explosive.

One of the oldest methods of making hashish is to simply take the marijuana plant and rub it between the hands until the hands become coated with the residue. Then simply scrape the newly made hashish off of the hands. 

It should be noted that this produces some really sticky hands.

Another simple method to make hashish is simply to run the marijuana through a series of fine filters. The marijuana trichomes, which contain the active ingredient, are quite small and will pass through fine mesh, while the non-medical plant material will be trapped. 

4) Ice water

Another method used to make hashish is to soak the plant in ice water while the filtering process is done. This makes the active nuggets harden up and separate from the rest of the marijuana plant easier. This is the idea behind such products as the ice-o-lator.

People don't usually think of vaporization as a way to make hashish, but that is, in effect, what it is doing. The active ingredients in marijuana vaporize at under 200 degrees. When the marijuana is heated, the active ingredients boil off before the plant material actually burns. This provides a very pure form of hashish, even if the hashish is in a vaporous form.