The Clays series of powders burn very clean in shotguns compared to some of the old versions of the Alliant Dot powders.
I would follow Gray Beard and give the Universal a try in handguns where you may have used Unique.
Supposedly newer versions of Dot powders burn cleaner. But a friend of mine was using one of the Clays (not sure which) in trap and skeet shooting and his barrel was amazingly clean after several rounds on the range.
I used some Universal Clays in shotgun and liked it. I think I used it in 38s and 357 too - seemed fine.
Seems like I've read good things about Benchmark in the 308 family too. You may have made a darned good deal.
liberal Justice Hugo Black said, and I quote: "There are 'absolutes' in our Bill of Rights, and they were put there on purpose by men who knew what words meant and meant their prohibitions to be 'absolutes.'" End quote. From a recent article by Wayne LaPierre NRA