Just give him plenty to drink he will vomit the rest the water will help my dogs have eaten all sorts of junk when of the lead over the years such as petrol filed puddles the brainless dogs that they are anyone would think i had never given them a drink or food in there lives.
i would put him in the washing machine on a quick wash then in the tumble dryer on a warm tumble. comb him well when he comes out and i bet he wont do it again