Only happened once in 50+ years. I tossed it. With blends I pretty well know what I'm getting when I order a tin. Jim keeps me on track and I trust his judgement. So, when I do order something new, I pretty much now I'm gonna enjoy it.
Now Jim... about that skunkbutted perique?
I stay away from tobaccos that have poor ratings - I have been using this tobaccoreview.com site for a while, and the feedback offered over there is pretty helpful. If I read a review of a tobacco that does not sit well with my taste I just don't buy it. This being said I rarely have unsmokeable tobacco ... should the case arise, I either gift it or mix it in my large all scraps jar. One day I may try that chaotic home made blend a try ...
I've got a few McClelland straight Virginias that I find lacking in flavour so I will occasionally mix them with something like for example #2015 VaPer, something like a 20/80 mix. I don't find that it diminishes the #2015 (or whatever I mix it with) at all but it uses up tobacco that I wouldn't normally smoke.
I did this with Beacon Extra and Christmas Cheer at a 50/50 ratio and the results were splendid. It took off the sharp edges of the BE and really smoothed it out.
Smoking Frosty Mint makes me think of a cake that's mostly made of icing. The first half is a blast but it goes sour quickly, usually I toss the last third of a bowl.
The First Third is Minty, and the second third is primarily just sweet, then it takes on a bitter flavor near the end (as with many Aromatics, but the effect may be exaggerated here because of the extreme lack of natural flavor).