Can you patent an item you made of a regular fabric and I am selling a lot?

I made an item of a regular disposable paper, this fabric like paper is nothing special or have any specific brand, I found a way to item that can be use by a lot of companies, I showed samples to companies because nobody is selling this item but me, and the order are huge, but before I deliver them I want to know how can I protect myself how can I protect myself, it not an invention but an idea that I develop and gave it a good use.