Since the question was about contaminated runway charts, it seems reasonable to assume they refer to a contaminated runway
Seriously, though, you are correct in that another of the standard problems is that the AFM always seems to have charts for every type of contamination except the one you have! To go back to the original question, yes there is a point where you have to stop operating and that point varies with aircraft type; I have to say that BA 0.05 and/or WED 3mm is a pretty awful runway, I think I'd quite happily go back to the coffe bar until the weather improves
