How to reset Nvram?

I was using Clover before with Catalina before, yesterday i tried opencore bootloader, which didn;t worked but it messed with the 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

submitted by /u/Elijah_the_original
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