How to Clean a Muffin Pan
It can be tough to clean all the baked-on grime off of a muffin pan, but you can get your pan clean with a few basic household supplies. To soak dirt and grease off of a tin muffin pan, fill your sink with warm water and submerge the pan in it. Put 1 or 2 dryer sheets in the water on top of the muffin pan, then let it soak for at least an hour. This should loosen up the grime so you can easily wipe it away with a sponge. Finish up by rinsing your pan with soap and water to remove any chemicals from the dryer sheets.
Fill the sink with warm water. Turn the sink water on both hot and cold and let it run for a few seconds, adjusting as needed until it's warm but not hot. Then, plug the sink so it fills about ¾ of the way up with the warm water. If the grease or grime is particularly caked-on, adding a squirt of dish soap to the warm water will help loosen it even more. Place the muffin pan and dryer sheets in the warm water. Lay the muffin pan in the sink so that the muffin holes are facing up. Try to submerge it as much as possible. Then, lay 1 or 2 dryer sheets flat in the water on top of the muffin pan holes. While 1 dryer sheet will likely work for most pans, if your muffin pan has a lot of old caked-on grease and grime, you may need to use 2 dryer sheets. Leave the muffin pan to soak for at least an hour. For best results, leave your muffin pan to soak in the water with the dryer sheets overnight. This will give the cleaning additives in the dryer sheets more time to dissolve and loosen a lot of grease. If you need to use them sooner or want to get them clean quickly, however, let them soak for at least 1 hour. Wash off any remaining mess with a spatula or sponge. While soaking with the dryer sheets, much of the grease and grime will loosen and fall off the muffin pan on its own. If there is any remaining mess after you let the pan soak, however, you can use a spatula to scrap off caked-on food, and use a sponge to wipe away any grease. After wiping off any remaining grime, you may want to rinse your muffin pan one last time with dish soap and warm water to remove any chemical residue from the dryer sheets. Dissolve baking soda in warm water while preheating the oven. First, set the oven to preheat to 350 °F (177 °C). While the oven is preheating, measure out and pour 2 tablespoons (25 grams) of baking soda into a bowl filled with 1 US quart (0.95 L) of warm water. Stir the mixture until the baking soda is completely dissolved. While you can bake some of the grease and grime off your tin muffin pan with just water, adding the baking soda will help loosen and remove more of the stubborn mess. Pour the water and baking soda mixture into each muffin hole. Fill each hole until it's about 2/3 of the way full. Don't worry if some of the grease and grime is on top of the pan – the steam from the solution combined with the heat from the oven will help you clean the top of the pan as well. Bake the muffin pan for 8 to 20 minutes. If your muffin pan has a lot of old caked-on grease, you'll likely need to bake the pan for 20 minutes. If you're just trying to get it clean after a single use, you may only need to bake it for 8 minutes. Remove the pan from the oven. Once the muffin pan and solution have baked, remove it from the oven and dump the baking soda solution in the sink. Then, place the pan on a heat-safe surface and let it cool enough that you can handle it but not so long that it's completely cooled. Make sure that you use oven mitts to protect your hands when you handle the hot pan. Scrub the muffin pan with warm water and dish soap. Squirt a dime-sized amount of dish soap on a sponge or nylon bristle brush and scrub the pan to remove any remaining grease and grime. While the baking the pan with the baking soda solution will loosen and remove some of the mess, there may still be some that needs to be scrubbed off. If you use a bristle brush, make sure that you choose a nylon brush so that it will scrub your pan clean without scratching the tin. Once you've scrubbed the pan, rinse it with water to remove any soap residue so it's ready to use. Place the pan in the sink under very hot water. First, turn the sink water on as hot as it will go, letting it run for a few seconds to heat up as much as possible. Then, carefully place the silicone muffin pan under the running water. If your sink water gets really hot, you'll likely need to wear rubber gloves to protect your skin. Letting the pan rinse under the hot water first will help some of the grease or baked-on food start to loosen, making it easier for you to scrub off. Scrub the pan with a sponge and dish soap. While the pan is rinsing under the water, squirt a dime-sized amount of dish soap onto a sponge. Then, scrub over the entire muffin pan, rinsing it off with the hot water as needed. You may need to spend a bit of extra time scrubbing inside the muffin holes, as the edges can be a bit hard to reach. Rinse the pan and shake it to remove some of the excess water. After scrubbing thoroughly, hold the muffin pan under the running water to rinse off the soap and loosened grime. Once rinsed, turn off the water and gently shake the pan so it's not drenched with water but is still a bit wet. Mix baking soda with a splash of water to make a cleaning paste. If there's still some grease and grime stuck on your muffin pan after you scrub it with dish soap and water, use a baking soda paste to help loosen it and remove it. To make the paste, pour about 2 tablespoons (25 grams) of baking soda into a bowl with a small splash of water. Use a spoon to mix the baking soda and water together, adding more baking soda or water as needed to create a thick paste similar in texture to toothpaste. Instead of making the paste in a bowl, you can also pour baking soda directly onto the pan as soon as you've rinsed it while it's still wet. Then, use your fingers or a spoon to mix the baking soda with the water remaining from the rinse to create the paste. Spread the paste over the grease and stuck-on grime. Using your fingers or a spoon, spread a thick layer of the baking soda paste over the dirty spots on the pan. Make sure that you fully cover any stubborn grease or grime. Let the baking soda paste dry completely on the pan. The paste could take anywhere from a few minutes to over an hour to dry, depending on how thick you layered it on. The baking soda will absorb the grease as it dries, which will make it easier for you to wipe off the muffin pan. Wash the baking soda paste off the pan with a sponge. Once the paste is completely dried and hardened to the touch, rinse it under hot water again to remove the paste. As it's rinsing, squirt another dime-sized amount of dish soap on a sponge and scrub over the pan again to ensure that all the paste is removed and, along with it, any remaining grease and grime. 
Fill the sink with warm water. Place the muffin pan and dryer sheets in the warm water. Leave the muffin pan to soak for at least an hour. Wash off any remaining mess with a spatula or sponge. Dissolve baking soda in warm water while preheating the oven. Pour the water and baking soda mixture into each muffin hole. Bake the muffin pan for 8 to 20 minutes. Remove the pan from the oven. Scrub the muffin pan with warm water and dish soap. Place the pan in the sink under very hot water. Scrub the pan with a sponge and dish soap. Rinse the pan and shake it to remove some of the excess water. Mix baking soda with a splash of water to make a cleaning paste. Spread the paste over the grease and stuck-on grime. Let the baking soda paste dry completely on the pan. Wash the baking soda paste off the pan with a sponge. 