I have some Velveeta in the basement that is old. Does it really ever get old? I think not. But it does look weird..."it looks like it has been melted." Here is a recipe using Velveeta that ensures your cheese fondue will not ball up, or become stringy or separate. Not that I have ever had that happen to a few pounds of cheese before.
Easy and Fool Proof Cheese Fondue
1 c. water
2/3 c. water mixed with 1/3 c. white vinegar and 1 T. sugar ( my substitution for 1 c. white wine)
3 to 4 garlic cloves, minced
1 T. butter
1/4 t. white pepper
1/4 t. ground nutmeg
2 pounds processed American cheese, cubed or sliced
2 pounds Gruyere cheese. shredded. cubed or sliced
These directions use a crock-pot for ease.
Preheat crock-pot on low.
Place water, wine substitution, butter, garlic, pepper, and nutmeg in a saucepan and bring to boil. Pour into crock-pot. Add cheese. Gently stir. Allow cheese to melt on low stirring occasionally. Stir just to mix. Add more cheese or more water to bring to desired consistency. Keep crock-pot on low or keep warm or place in a chafing dish with the flame low.
Dip rye bread, French bread or sourdough bread. These can be cut into bite-sized pieces. Apples that have been peeled and sliced are wonderful for dipping as well.
Don't bring cheese temperature past its melting point or it will ball up. Don't stir too much. Stirring increases the chance of it becoming stringy.
If you don't use a crock-pot, bring all ingredients except cheese to a boil in a double boiler. Add cheese a little at a time stirring until cheese is melted. Pour into a chafing dish with the flame kept low.