Well, they would be deleted from the folder where your Internet files are kept. Every time you visit a webpage, even if you don’t go ahead and save the file willingly, a copy of all the text/pictures/videos you view on webpages are put in a folder on your computer.
I’m not sure if this is in the same folder or another folder, but your (encrypted) passwords are also stored on your computer somewhere - probably hidden so you couldn’t actually go and find them by opening My Computer, for example, but it would have to be on your computer somewhere so the next time you turn your computer on, it’s saved.
Now, as for whether everything you view is deleted when you clear the Internet cache, the answer would be yes and no. As with if you delete anything on your computer, it’s not really deleted and gone forever, but it’s put into somewhere on the computer where the casual computer user could not get to it. Like, when you delete something from the recycle bin, it’s essentially “deleted” but if it needed to be extracted again, it could be.
You would need to download a program to do this, but sometimes only parts of the file can be found again, which is pretty much useless. So, in essence, once something is put on your computer (whether it has been downloaded from the Internet, or copied from a USB drive) it will always be there.
If you really wanted to delete something, say if you wanted to donate your computer to charity and wouldn’t want someone to go and extract all of your “deleted” data, you would need to wipe your whole hard drive with a program called Boot ‘n’ Nuke. This program doesn’t delete the information on your computer, but runs sequences of 1s and 0s over it, kind of like gibberish. You need to run the about 10 times to make it very unreadable. Only someone with a lot of time, and the proper equipment could unscramble and extract your data again. Like the police force, or secret service. it would take a while, but it could be done.
My uncle actually works for the Australian Security Intelligence Organisation, and he said the process they go through to delete data is very intensive. Basically the way the only real way to delete data is to melt it at a very high temperature, or cut it up.
It’s actually quite interesting… Hope that helps. I’m not actually sure if I answered your question, though. Heh.