Hose the negs off in a seperate room. I do full image test prints (seldom do I use test strips). This way I can make damn sure the neg is clean prior to printing many. I figure 10mins max will get any neg clean which beats the hell out of 1min of spotting. I also shoot at least 2 of everything so if one frame is hopelessly dirty/stained whathaveyou I have a back-up. Mostly I don't have dust issues though -- oops I probably should not have said that.
Having your black areas turn blue is an indication of under development. It will happen with too low a temperture, too short of a time, inadequate agigtation and developer that is being exhausted.
I got a styrofoam plate that I keep in a 8x10 box that has all the colours found in an ancient liquid spotting kit from Kodak. Each colour occupies about 1 sqin area in a dried pool. I suspect that this quantity should last about 10-15 years. It has already lasted 4 and the pools are hardly touched