We do quite a few. Did one today. With the right chemical, the nicotine is not a problem. We use neat citrusol. It gets brown back to white, not yellow, white.
For frames, spray it on with a trigger bottle, leave 5 mins, wipe frames down with a fairly wet microfibre cloth, then a damp one, then a dry one.
Use it neat on your applicator too. Pole it on to the roof panels, squeegee them off, twice. Your water will be minging. Get fresh water with fairy in, go over the panels again like normal and hey presto!