Occasionally I get a batch of pots which don't work out. It's generally ok to re-fire and in most instances it actually can improve the surface of the pot. Warming the pot and then applying another coat of glaze can work wonders too, although take care not to rub off the dried glaze as this can happen quite easily. Worth a go...these are all re fried pots...
The online Blog from Uk Raku potter, Shaun Hall.