How can I convert a scanned PDF with OCRed text to one without OCRed text?

I have a scanned PDF file , with low-quality OCRed text. I would like to have a PDF file without the OCRed text. How can I convert a scanned PDF with OCRed text to without OCRed text? I am thinking about what ways can recover the original scanned PDF file before OCR as much as possible, without changing the width and height of each page in pixels, and without changing the pixels per inch of each page? Is some kind of rasterization again help? Will rasterization again loose the image quality? Several attmepts: 1. I use the print to file in Evince, which I think uses cups-pdf, it doesn't remove OCRed text. 2. Following command using gs doesn't remove OCRed text either (I think I haven't found out how to use gs properly): gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 \ -dNOPAUSE -dQUIET -dBATCH -sOutputFile=out.pdf toc.pdf