I can't clear the "Numbers Recents" files in the Numbers App on my iPhone

I believe it shows simply the last x documents you have opened, regardless of how much time has passed. If you want to remove them from your “recents” screen, simply move them out of your “Numbers” folder and into another folder on your iPhone. It will most likely copy them to the new location, rather than actually move the file. Now delete the original in the Numbers folder (after confirming that the copy was successful, of course). This will remove them from your “recents” screen, until you open them again.

I tested my solution before posting it. In this testing, I moved a document from the “Numbers” folder on my iPad to another folder which I newly created, also on my iPad. iCloud was not involved in any way. The file remained on my iPad, merely copied to another directory. Deleting the original file then removed it from the recents list, as Numbers properly recognizes the copy as being a separate file. Renaming a file, however, as you attempted to do, will not work, as it is still the same file.

As you can see if you read my original solution again, I suggested moving the file from your Numbers folder into a different folder on your phone. Not iCloud. Give that a try. I would be very surprised if it did not work for you.

I was mistaken. The file I tested with was moved (copied) from my iCloud to my iPad. So I was wrong in suggesting that iCloud was not involved. However, I did some further testing.

I concluded that moving a file from one iCloud folder to another iCloud folder will not remove it from “recents”. I felt that requiring you to store this file locally to solve your problem was inadequate, so I played around with it and I was able to remove a file from recents by moving (copying) it to my device, deleting the original, and then moving the copy back to the original location, which is the “Numbers” folder in iCloud.

So essentially what I have done is delete the original file, and replace it with a copy, in the exact same iCloud directory. As it is a copy, it is, for human purposes, the same file. For machine purposes though, of course, it is not - a copy is viewed as a separate file. Because Numbers does not recognize it to be the same file you opened, it does not appear in recents.

Be aware that moving files around like this will increase the risk of data corruption, which is low, but always present. If a file becomes corrupted, you’ll know it - it won’t open. This happens when it fails to properly save. Always have a backup of any important documents stored someplace safe. It really wouldn’t be a bad idea to store copies of important files locally on your device. You can password protect them if losing your device is a concern. I like to e-mail important documents to myself, or export them to my saved messages in Telegram. Some documents I have worked on for years. I don’t trust a single server to preserve them in perpetuity.