Hi All, I do lube my bike but it has gone all thick black around the cogs and chain and looks like thick black grinding paste now! Its all over the plastic disc thing behind the largest cog on the rear aswell and although I cba cleaning it really, its niggling at me cos its looking pretty rotten now... Should I clean and re-lube or is not necessary really? Also when it was new my bike would glide along without any clicking when pushing it.... Now it has started clicking and is this good or bad or what? Should I lube something in the wheel or is it not a big issue really? Any guides around with info on all this stuff?