custom post type and categories

I have a custom post type: Products
I have a custom category display which works fine, but only displays normal posts but nothing from the cpt products.

There are about 40 categories so it does not make sense to make them all into cpt, particularly since the category display works fine.

How to I get the category page to show items from the cpt: products?

So I will have 20 different category displays and each one will display only items in that category form the custom post type products.

IE. All the items from category: Hairspray to show on one page/post/display.
then all the products from brushes: to display on a page/post/display that only has items in that category.