What do you propose?
It would depend wether you disliked the Guinness because
1. The quality was sub-standard in your opinion, after tasting Guinness over the years.
2. You just don't like the taste of Guinness.
if,
1. I would draft a letter to CEDC ( Central European Distribution corp ) who are the distributors of Guinness in Poland, explaining your reason(s) for finding the contents sub standard, together with the second can as a sample.
2. Bearing in mind your frugality, you have to give the second can away as a present, but only to someone you want to -**** off...
Hope it assists in your decision.