Hiya,
I'm building a Riva Aquarama (see my icon) which has a beautiful mahogany varnished finish. I've applied 3 coats of cellulose sanding sealer followed by 4 coats of yacht varnish. I've taken the hull outside and sanded down between coats with 600 grade paper then wiped down with paper towel and used a sticky roller to remove any remaining dust. The varnish looks good but is marred by very small specks of dust which are presumably airborne. I remember reading somewhere that it is a good idea to finally sand with a very high grade paper and then polish it. My question is what grade of sandpaper - I have some 1000, 2000 and 2500 grade papers. Also can anyone please recommend a suitable polish? Should I look for a car polish, boat polish or some type of furniture polish. There are lots of metal fittings to glue on so presumably sand first and then polish. In the end, I don't want to be left with white polish residue around difficult to access places. Any advice welcome. Thanks in advance Duncan.

I would suggest wiping down with a tack rag just before applying the varnish. If you are in an area with a concrete floor, wetting down the floor will help keep down the dust.
If you need to rub out the finish to achieve the shine you want, use increasing fine sandpaper ending with the 2500 grit that you have. then rub it out with polishing compound for the final shine.
Polish shouldn't be necessary, but auto polish will do, not furniture polish.
Polishing should be done after all attachments
Trev