Ancient cotton cloth, as in triangular bandages, is probably fine if it's not been attacked by vermin.
Any scarf will do for a sling so I don't think this would be a problem if there are no holes.
Anything elastic can degrade and should be replaced.
Thanks, I was hoping for your expert advice. Yes, I've tossed everything perishable. The burn dressing was rather sorry-looking and the Hansaplast looked like a relic from the
Santa Maria. The main thing that delights me is the crooked scissors, for one of our dogs has a dressing on his leg that is due to come off this weekend. The dressing, that is. That is also why I was pleased to find the bandages, just in case it needed renewing. We have Betadine & sterile compresses etc.
@Pancho Yes, the kits are still mandatory in Germany, but we no longer live there. The police are quite capable of checking their contents, too. Back when AIDS was penetrating the public consciousness they introduced a rule that all first-aid kits had to contain a pair of sterile rubber gloves, and a week later a chum was stopped and fined for not having any.