Paul's BBQ Meatballs

1 pkg. pre-made frozen meatballs
1 cup ketchup
1/4 cup white vinegar
1/2 cup brown sugar
2 tbsp chopped onion
2 tsp lemon juice
1 tsp Worcestershire sauce
1/4 tsp black pepper
1/8 tsp ground allspice
1 pinch celery salt
1 pinch mustard powder

Combine all ingredients except meatballs into slow-cooker, whisk together until all combined. Add meatballs and stir to coat. Heat on high 2-3 hours or until heated through.

Michelle's notes: I always forget to pick up some allspice at the store so I have always omitted it and it still tastes fantastic.