How to remove current theme customizations

What do you mean by “customization”? Modifying the theme’s PHP, or modifying some settings the theme creates? Most themes do not clean up after themselves when they are deactivated or deleted. So for many themes, there is no easy way to flush their data. This is actually a good thing, if you want to switch back and forth between themes, but it forces you to pay attention to what you install on your system. If there is no content, you could start with a new database, that would certainly reset any theme options.

tech