We know. You run hot water behind it to wash it down the drain, but grease coats the inside of pipes and can lead to a clogged drain. As it cools down it solidifies and create a real problem.
It may say it is flushable, but flushable kitty litter can clog your drain and cause problems if you have a septic system.
Coffee grounds do not dissolve and can accumulate in piper bends and create a clog.
Even though your garbage disposal grinds up eggshells, they will not dissolve in your drain. They accumulate in pipe bends and give grease and other substances a place to stick.
Most paints are water based and you can wash them off with water so you would assume they are safe to flush down the drain. In many cities it is against the law to flush paint down the drain. Remember that Kitty Litter you need to get rid of? Use it fill empty paint cans to absorb any leftover paint.
You will see them term biodegradable on many paper towel and cotton ball packages. That does not mean you should flush them down the drain. They will absorb water and clog your pipes. Notebook paper will not dissolve easily in water. Put in the garbage can.
It is great for baking pies and cakes, but you know what happens when you add water. It becomes a globby mess and will clog your pipes.
The stickers from fruits and vegetables will clog your drain. The pits will also get stuck in pipe bends and prevent your sink from draining.
These are starches and will swell up and prevent your sink from draining.