What items cannot be returned to Costco?

Could you please clarify for me what specific items are not eligible for return at Costco? I'm curious about the categories or types of products that they have a no-return policy on. For instance, are electronics, perishable goods, or certain types of clothing among the items that cannot be returned? Additionally, are there any specific conditions or exceptions to their return policy that I should be aware of? I'd appreciate your insight on this matter.