I do it the hard way.

I delete all of the stuff in the library folders, then I venture into the Geometries and Textures folder. Sometimes I'm lucky and can find the stuff, other times not. If I can't find the files I pull out the original .exe or .zip file and install/unzip it to a folder on my desktop and look in the geometries/textures folders to see what I'm looking for. Then I venture back to my geometries and textures folder and delete the folder/files.

I don't really uninstall that much because I use multiple runtimes. Though I do have a ton of props that I installed that I haven't used in a God's age, but I leave them installed "just in case", lol

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi