As far as I can tell sweets 7.62 has been out since the 1980s. I’ve been using it since about the late 2000s and had success. However I feel a close competitor to Sweets 7.62 is Bore Tech as it is the only thing comparable if not better and safer. I also notice a lot of folks use tight fitting jags or putting a wet patch and scrubbing the bore.

https://www.amazon.com/Sweets-OK-762-7-62-Solvent/dp/B001OPNO44