Before there were 420/710 name brand cleaning products, there were home remedies. There are many solvents out there that break down the components of cannabis; my go to, isopropyl alcohol (the higher the percentage, the better). Used with salt, and ziplock baggies. Pretty much anything used to make concentrates can be used to break down the cannabis residue in your smoking utensils.
Place your pipe in a ziplock baggie with a tablespoon of salt (again the better grade, the better for your needs); the salt acts as an abrasive that helps break up the residue in your pipe.
The next option is my least favorite because it requires a slow simmering pot. Water is also another solvent of cannabis, hot and cold. There’s a method of making hash using ice water to break down the trichomes, but that’s a different article.
In a pan or pot bring enough water to cover the unit to a slow simmer. According to this Wikihow article, let it soak for 20 to 30 minutes. Then you can use something to poke out the gunk and rinse with hot water, not cold because it could shock the glass to shatter. The Wikihow article references some other ways, but the first two are my go tos.