If you prefer not to use third-party software, you can manually purge the mod files from your main directory. :
: A lightweight script that "cleans" your installation for online play and can even "restore" those mods later for single-player use. GTA5 MODS UNINSTALLER
Several community-made tools can scan your directory and remove non-original files with a single click. If you prefer not to use third-party software,
: If you used OpenIV, open the program, go to Tools > ASI Manager , and click Uninstall on all three components (ASI Loader, OpenIV.ASI, and oIV). The "Nuclear" Cleanup (Recommended for Online Play) open the program