How do i get rid of these black shadows? I'm trying to render an animation about this children's crib. Essentially I'm creating a "How to install" guide as the printed one is dated and difficult to understand. 

Using Blender 2.78 in cycles, I can render my object just fine. As I'll want to show where certain screws go and how the parts slot together, I want to use transparencies.

First I combined the diffuse shader with a transparent shader through a mix shader. At 50% and at 100% transparent I get these results.

So essentially if I tried to make the whole object transparent, I get these "shadows" remaining on the render.
So I decided to focus on one panel. I went 100% transparent for the Grey color and it works fine. When I try to do the same with the chrome color, the color or hue disappears but again i'm left with a kind of shadow from where the objects where. 
I've removed doubles, made sure nothing is overlapping but I'm still stuck. Think it has something to do with shadows or the way I'm using the shaders. Anyways I fairly stuck and would appreciate any help. Thanks, Adam.

It won't let me post another pic yet as I'm new to the forum but my settings are as follows:
Transparency Max:4 Min:1, Bounces Max:4 Min:1, Diffuse:4, Glossy:4, Transmission:4, Volume:0, 
Shadows: Checked, Reflective Caustics: Checked, Refractive Caustics: Not checked, Filter Glossy:1.0,
By increasing the Transparency Max from 4 to 24 (with some trial and error), I was able to successfully eliminate the all of the shadows from my animation. I originally tried increasing the Bounces Max to 48 with no success, so I dropped it back to 4, then increased the Transparency Max amount and everything worked.

Thanks to everyone for their help and suggestions.