RAM is running low. and I want to get some back.
But do any of these methods actually work?
Not for your problem.
And to that, what is telling you you are running low on RAM. If you are not getting any errors, you likely don't have a problem.
The reason to clear RAM is really for security - so a bad guy stepping up to your computer as you run to the bathroom cannot access some sensitive data that might still be in RAM.
Clearing RAM because you are running low on RAM is not how memory management works. Windows will automatically dump lower priority data as space is needed. The user does not need to do anything.
If you are running low on RAM it is more likely you have too many programs starting with Windows, you dinked with the Page File setting when you should just let Windows manage it, and/or you are running low of free disk space.
8GB of system RAM is typically plenty for W7 work just fine in. So check your startup programs and disable any you don't regularly use. You can see what they are in Task Manager.
Run CCleaner or Windows Disk Cleanup to clear out the clutter on your drives. If you dinked with the Page File settings, change them back to Windows Managed. If still low on free disk space, uninstall any programs you installed you don't use. If you don't know what it is, Google it. If you still don't know, leave it.