First, make a solution of about 100 ml of cold water, I recommend distilled, and am not responsible for conflagrations caused by tap water use. 100 ml is about a cm of water in a coffee cup. Stir in your NaOH (1/4 teaspoon or 2 mg). It will take a bit to dissolve. NaOH will heat up the water real fast so if you are using larger amounts be very careful.

Now pour the NaOH solution slowly into your Robo while stirring. A white milky powder will form where they hit. The extraction will occur quickly. There is very little DXM in Robo and it will all be done quickly. If it IS NOT REALLY OBVIOUS THAT white powder is coming out of solution anymore, than you are done. It will not take much so don't keep pouring in more solution.

Now pour your solution through the filter and funnel. This will take a bit of time. Then rinse the container in case some powder was left in it. Then pour water through the filter until all the red dye is pretty much gone. Let the filter drain for bout an hour.

Open the filter up and let it dry on a plate. You can heat it a little (150 degrees) to speed this process. Then scrape off white powder.