Okay, It really isnt that hard to do but it is a few steps that i can walk you through.
1. draw a line from the left side of the can to the right side. Make sure that both ends overlap the edges.
2. Now with the line still selected, Object>Path>Divide objects below. This will divide the spray can into two different objects.
3. Copy the entire spray can.
4. Now place the spray can behind the star
5. select the star and the spraycan that should be behind the star. With all selected Object>Clipping Mask>Make
This will make your star disappear but just add a stroke to the star that matches the size of the black line in the star.
6. Now press Apple and "V" and same time or Edit > Paste in front. This will take the copied image from Step three and place it infront of your star.
7. Use the Direct Select tool and click the pasted can but click below the dividing line and press delete. This should make your desired effect.