Decrease thickness of object The following object, in obj format, is 1.6 mm thick and I want it to be 0.8 mm thick.  How do I decrease its thickness (from the inside, so that the outward appearance is still the same)?  When I go to Add Modifier-&gt;Solidify, it only allows me to increase the thickness, but not decrease it.
Note:  The suggested previous question does not help me much because I have thousands of faces along the edge to delete when in Edit mode (the original file was obj).
Decrease thickness of object

I have made a half sphere and added some solidify modifier and applied to it. To decrease thickness or shrink down the thickness. In edit mode -> select all and press Alt+S or Mesh -> Transform -> Shrink Fatten



As soon as u click on or better press Alt+S like we scale we get a arrow to increase or decrease the thickness. After click u can press F6 for operator panel or adjustments. Click Ctrl+N to flip normal.