I have accidentally deleted Firefox cache and lost some log ins. How can I retrieve them? https://support.mozilla.org/bm/questions/1080444

"Firefox's cache consists of temporary copies of files, such as pages and images, and when you visit site again, they will be downloaded again."

Knowing that doesn't mean I know how to do it.

"There's no way to undo clearing the cache"

I didn't go into the settings to clear it like the OP of that thread did, but I want to restore it to last month.

You can't restore older disk cache content just like you also can not recover deleted history although for a latter you might be if you have an older places.sqlite backup. The disk cache is also much more complicated and in case of issues with the cache like if you mess with it then the disk cache is invalidated. Firefox also keeps a memory cache and as its name indicates, it is kept in memory and purged automatically when you close Firefox.