Get a good Temperature Controlled station and extra tips.
The good TC stations like the Weller, all you have to change is the tip to avoid cross-contamination, and the tips are fairly cheap. Just keep the factory bags for ID, and stick them into marked bigger baggies so you know whether the used ones are Lead or No-Lead when you swap them out.
Me, I wouldn't worry too much - if you clean the tip well and re-tin a couple of times to "wash" it with the no-lead solder (Lather, Rinse, Repeat) that would satisfy all but the most anal retentive inspections.
Or get a seperate iron that's ONLY for working on ROHS devices. But you need to be making enough dough for that to make sense.