If you're referring to Safari browser cache, you can open up Safari preferences, go to the advanced tab down at the bottom and enable "show develop in menu bar". Then just click the "Develop" menu and then click "Empty cache".
Another option I've done in the past go to the library folder in my user account, opened the cache folder and deleted the "com.apple.Safari" folder.
Your talking to a senior citizen..So if I do what your saying I won't lose my passwords that are stored in my computer? Last time I hit clear history and cookies I lost everything what a mess that was.
I have no idea how to get to the library or folder
If you take the steps I told you about the "develop" menu you will not lose your passwords. You won't even lose them in the second step I described. But the first step is the one I suggest for you. And just so you know I'm 53 myself.
Just make sure you DO NOT use the "clear history and website data" that is in the "Safari" menu.