Another method that hasn't been mentioned yet is to use a chef's torch on a medium high setting and blast it until clean.
Not sure how this isn't the widely accepted cleaning method lolJust rinse that shit out. Water, run through, give a good shake, let dry. However, if you're going to be one of those people who feels there is value in reclaimed the residue, this next part is for you:
Stop messing around with all the implements scratching around inside your pipe. Its never worth the time you'll spend hopelessly attempting to direct some of that dust into the bowl for what will ultimately be a small, harsh and self-defeating hit. Instead, use the exact technique I mentioned above. But use distilled water. Dirty pipe + very small amount of distilled water. Shake while covering pipe openings. Shouldn't take long to see all the residue gone, meaning it's dissolved in the water. Now you need a plain glass plate. Yes, GLASS, not china, not porcelain, not stoneware, not pewter, only clear glass. Saucer size is perfect. Take your pipe and gently tip out that water onto the glass plate. Put this somewhere out of the way. A rarely used cabinet or closet work great. If you have the space and equipment, you can aim a small, not too powerful fan at the plate. The water will evaporate and what's left will be the stuff dissolved in that water. As to the contents of this result, its safety of consumption, or it's value for even taking the time to gather..... Well all those are what you, the user, had to decide. For full disclosure, back when I used meth daily, I kept a reclaim plate I'm my closet with a very small desk fan pointed at it. Let's just say, whenever I ran out of gear I would spend a fair bit of time scraping the plate.
Have fun and stay safe out there!