How can you clean a double glass sliding door inside.

I don't, mine are sealed. If there is stuff been the panes the seal has been broken and need to reglazed.

USE A TOOTH BRUSH TO GET ALL THE DIRT OUT OF THE RAILINGS. THEN, USE ANY KIND OF OIL TO GET THEM RUNNING SMOOTH.

Can't! The seal has failed between the glass. The inert gas (usually argon) has leaked out and air got sucked in. The glass pane needs to be replaced.

I clean mine by having both sides closed at the same time. That allows access to the entire area of both doors on my sliding doors.

You can't clean between the panes, but like Shirley Gilleland said if you are just trying to clean the doors on the side inside the house, then you need to close them. I remember having an old door that overlapped the other door even when closed. I used a cloth on a yard stick to squeeze in. On the newer doors it is mainly just the frames that overlap. Once a year we removed the door, but it was heavy and hard to put back, so we ended up just using the yard stick.