i have a 60 watt Weller that works great but the tip need replacing and always turns black after each solder. the sponge doesn't seem to work cleaning the tip.
I've also got one of those 60 Watt Wellers. It's OK, but I've also got a Weller 100 Watt temperature regulated soldering iron. This soldering iron also has iron plated tips, rather than bare copper. Those tips last a long long time.
Nice thing about temperature regulation, the soldering iron doesn't just keep getting hotter and hotter during none use, but levels off at about 700 degrees F. Soon's you try to solder, that tip cools off a little bit, the soldering iron powers up, and keeps it at 700 F.