The soft reflector is made of reflective vinyl (PVC).  but when you put the silver reflective item like slapwrap, hanger, sticker etc together with the lime color reflectors,  the silver ones will have some yellow color on the surface after some days, weeks , sometimes even some hours.

it is the character of the PVC material for the color transfer.  it is almost not possible to change it. The best way is to have a packing like polybag for each items when you have different colors items need to be packed together.

here we have some comments for this problem.

1, do not put different colors reflectors together, even different colors material like fabric, color paper etc , because the ink or dying material will effect the reflective pvc.

2, for slapwrap with white pvc backing,  should have a polybag packing for each item, or have a small paper to devide them.

3, keep the reflectors in a cool and dry condition,  the hot temp. will fast the color tranfer a lot.

4, have a white paper on the back of the reflector when you have a blinster packing for it. (only it is not necessary when the cardboard is in white color where the reflector touches)