Editing program used Adobe Photoshop CC (Adobe Photoshop CS3 and up)

Below is the original image and we will be using this image for this example.

Steps:
1. If this is for ecommerce use you have to select RGB color mode. (Image > Mode > RGB color)

2. Clean up the image fist by using Spot healing tool , Patch tool  or Clone tool .
This will depend on how hard to remove the dirt on the image.
(TIP: Use new layer, on this way you will you will always go back to the original photo)

3. After you clean up the image, Place your image on a plain white background. Using your Pen Tool zoom in to the edge of your product and begin to clip in.
(Tip: for a cleaner cut out path slightly to the inside of your image)

4. Right click on your clipping path and click on Make work path to save the clipping path on your image.

5. Select your image and make a Layer mask.

6. Add a Solid color (we will use white color background) below your cut out.

This will be your output:

7. Extract the shadows from your image. Copy the original image and crop the shadows and place below your edited image

8. Make a Layer mask on the image and brush the excess background

Leaving only the shadows.

9. Change the blending mode into Multiply.

10. Make sure that you also clean the shadows using the same tools as said above

(Spot healing tool , Patch tool or Clone tool . )

Before:

After:

11. And this will be your Final result.

Before and After: