I would like to ignore the stock level of certain parts. So that when a MO is processed, there is no decrement of stock levels. I realise the easiest way would be to remove the part from the corresponding BOM but I would like to keep the part in there.

For example I want to make a Book. The book's BOM contains 10 peices of paper, 1ml of ink and 2 staples. I would like to produce this part without decrementing the stock count of ink. (Which will always stay at zero)