I've stripped and sanded my dining room table, and have put down 5 coats of minwax gloss one step (classic oak color) lightly sanding between coats. The problem I'm having is that there are small areas that aren't taking the poly and leaving "dry" areas. If I put a final coat of satin poly or semi gloss poly would it cover these areas? Any other suggestions?
Good question. My thought is a little too late for you, but I have found that some woods excrete "oils" for a long time. You can usually see these after sanding, but it requires a close look, not only from the top but also across the surface. If you see anything different from the rest of the surface, then you can try more sanding. If that does not work, then you need to seal the whole surface until the problem area is no longer visible. When finishing, my first and second coat are usually 1/2 product and 1/2 thinner. I find this helps soak into the wood and acts like a sealer. If there are spots then you need to address them before proceeding.
This can also happen when refinishing a hardwood floor. The trick is to "pre-wet" the area with mineral spirits, and waiting for the floor to look 'wet' before applying varnish.
At this point, you probably want to thin down the 'dry areas' until the thinner starts making it look wet, then apply another coat.