Electronic Soldering Flux:
Alternatively, you can melt the rosin directly with a soldering iron to liquify and then dip in the solder, a lead, or wire.
You can soften the rosin by adding something like vaseline / petroleum jelly to it when molten for rub-on application.
Lastly, you can take an alcohol based mixture of rosin, add water, and evaporate at room temperature to make a water-based emulsion.
Athletes (baseball, gymnastics) use rosin in the form of 'rosin bags' to enhance grip on sports equipment. If available, rosin bags provide the no-fuss source for raw rosin.
Step 1: Collect
Locate a pine tree with 'wounds' from tree trimming. These contain the pine sap / pitch mixed with wood chips, pollen, bugs, and dirt. Use a butter knife to scoop the sap / pitch into an appropriate container. An appropriate container should be made of glass or of high density polyethylene plastic (HDPE). This type of plastic can withstand strong solvents like acetone and is generally marked with a '2' in the recycling symbol.
Step 2: Dissolve
Add acetone to the collected sap / pitch such that it fills up the container half way. Afterward, shake the container in 15 minute increments to help dissolve large chunks. It's impossible to dissolve all chunks, since some are very thick or are composed of wood chips so check the consistency periodically. When satisfied with the results, continue to the next step.
Step 3: Filter
For this step, obtain another HDPE container with a cone-shaped top (such as windshield wiper fluid). Cut the lid-grip off, then cut the upper, cone-shaped portion off and invert it so that it behaves as a funnel into the container. Next, insert two paper coffee filters and then pour in the dissolved sap / pitch solution. If the solution is too viscous, add more acetone. It should flow at least 2-3 drops / second when full. When 1/4 full, using gloves, wring the filter to squeeze out the remaining liquids.
Step 4: Container
For this step, you will need crisco / vegetable shortening, aluminum foil, and a suitable container for heating. Apply a coat of crisco to the inside of the heating container, then cover the inside with a continous sheet of aluminum foil. You can use the outside of the container to preform the foil. Add two more layers of foil and crisco. This will insure that the sap / pitch will be able to easily pop out of the container once the mixture has become rosin.
Step 5: Make Rosin
In this step, you will need vegetable oil, the heating container, and a deep fryer. Place the heating container into the center of the deep fryer and fill it with the filtered sap / pitch solution. Add enough vegetable oil to the deep fryer (but not the solution) so that it comes up to at least half the level of the solution. This will insure adequate heat transfer from the oil to the solution.
In the first stage, set the deepfryer to 'low' about 200 - 250 ºF. At this temperature, the solution will boil off acetone. Do this in a well ventilated location away from open flames to reduce the risk of fire. When the solution stops bubbling like water and becomes more syrup like, proceed to the next stage.
In the second stage, set the deepfryer to 'medium' about 275 - 300 ºF. At this temperature, the acetone disapears completely, and many of the toulenes and miscellaneous compounds that make pine sap permanently stick evaporate as well. When bubbling has receeded / lessened considerably, proceed to the next stage.
In the third stage, set the deepfryer to 'high' about 350 - 400 ºF. At this temperature, you eliminiate most of the non-rosin organic compounds. Bubbling should be miniscule towards the end. To determine whether this stage is complete, use a toothpick to probe the mixture. Check to see that the sample on the toothpick is not sticky, and that it crumbles with pliers into a yellow-brown dust. When finished, turn off the deep fryer and let it cool to the touch.