Safe cleaning apps

What do you mean by “cleaned”. Here is how to clean an iPhone→Cleaning your iPhone - Apple Support. If that isn’t what you mean, it is never necessary to “clean” the software in an iPhone. It is self-cleaning (perhaps like your oven). And there are NO trustworthy 3rd party apps among the ones that claim to “clean” iPhones, just a bunch of apps that will waste your money and slow down your phone (and possibly steal your data).

If you received a popup alert or warning or anything for that matter alleging your iPhone needs to be "cleaned", it's a scam.

Here's a recent example:

Just close the popup and forget it.

More information here: Phony "tech support" / "ransomware" popups and web pages - Apple Community. They can appear on any device — an iPhone, an iPad, a Mac, an Apple Watch... anything.