The New York City Transit Riders Council announced the dirtiest subways in New York at the 205th Street station in the Bronx, which a NYCTRC spokesman called "the most decrepit station I've ever seen in all my travels across the city." The NYCTRC has released a 2004 Station Conditions Report (PDF) of conditions in 50 city subway stations. Four of the dirty five are in the Bronx (number 1 being Moshulu on the 4) and one is in Brooklyn (the L stop at Atlantic Avenue). Some of the signs of a poor station, from the 29 factors: Peeling paint, rusted metal, eroding pillars, old subway maps, water drips, outdated subway maps. Gothamist can only hope that subway repair happens in the Bronx (interestingly enough, the Post noted that at the NYCTRC press conference, there was a cleaning crew at 205th Street), but we guess that the MTA focuses efforts on stations with lots of traffic. How the MTA gets anything done with a deficit, we don't know, but we know that making sure existing subways are taken care of should come before other efforts.
Grand Army Plaza's 2/3 station in Brooklyn and the 21st Street-Queensbridge F in Queens tied for cleanest. The cleanest stop in Manhattan is the West 81st Street B/C at the Museum of Natural History; the dirtiest is 47-50 Street Rockefeller Center's B/D/F/V station. Check out the report - it's actually fascinating reading, with lots of suggestions on how to continue to improve stations, which have improved since the NYCTRC's last study in 1994. And here's the Straphanger's State of the Subways Report Card.