Think RE-Deck, nnooo, not a new miracle product, A new deck surface....if the only complaint is the uppermost boards, (the ones you walk on) any more cleaner/stain/sealer/varnish cost can be applied directly to new board purchase. Even if you get the old deck looking decent??? in your words "it is an old deck" I'm not a big fan of wood substitutes, but the newest generation of composite deck material is good looking, long lasting, and with the cost-to-usable-life getting better (as opposed to the problems faced with salt treated lumber) think about treating yourself to a "NEW" deck???
good luck!!
mobjack68
good luck!!
mobjack68