Pork Barbecue

3 lbs. Boston pork butt (center or end cut)
1/2 bottle catsup
1 1/2 bottle water
1 tsp. celery salt
1 tbsp. chili powder
1 tsp. onion salt
1 tbsp. butter
1 tbsp. vinegar
1/2 tsp. salt
Dash of pepper

Boil pork 2 hours or until meat falls off one. Remove fat and gristle. Shred the meat. Mix together all sauce ingredients. Add to the shredded pork.
Simmer 2 hours. Serve on hamburger bun.