I have a Medion 90070 flatbed color scanner and I need to clean the glass on both sides. Does anyone know how this glass is removed or how to gain access to the bottom (inside) of the glass?

Did you mean Medion 9007 ?

Do you have the manual?

I find similar models here but they charge for the manuals unfortunately:

medion 9007 scanner manual - CD's & Download's P

Here is a general Google:

clean scanner glass - Google Search

Here is a guide to the underside of an HP:

Cleaning The Underside of an HP's Scanner Glass

Let us know if any of this helps.