How to reset Nvram?

I was using Clover before with Success' href='/2020/12/install-macos-catalina-on-supported-pc.html'>Catalina before, yesterday i tried OpenCore bootloader, which didn;t worked but it messed with the Success' href='/2020/12/install-macos-catalina-on-supported-pc.html'>Catalina, i clean installed the macOS several times but the boot args of OpenCore are still in the system, Kindly help me what should i do to remove the old OpenCore data? How to reset the NVRAM. and will it work?, plz help

Author: @Elijah_the_original