Minhagim

Question

With regard to different meat and dairy sets of dishes you say that minhagim are part of halakhah (an obvious point), but what about all the minhagim (e. g., covering counter-tops, kashering sinks etc.) which you are rejecting in your answers? I assume you will say that these are not real minhagim, but just practices carried out by people (mostly women in the kitchen) who didn't know the halakhah. But then how does one determine which minhagim are part of halakhah, and which minhagim are not, and can therefore be rejected?