There is a string on this forum that speaks to this.
Topic: Restoring a very old barrel -- feasible? (Read 14359 times)
I would do further research via google to see how to properly recondition a barrel. Since it is small (5 gallons), I think securing the rings properly, then submerging it in a hot water bath (hot enough to kill unwanted microbes and extract unwanted toxins, say 150F or so) would be a good place to start. Again, google it and see what is truly recommended.