The best way to impose materials

[smurv]

I got very big skp file, with mass of components

The question is how impose materials, because sometimes i got problem...

Usually i make like this:
make model + components
make all materials i v-ray window
impose materials by layer or components

but sometimes when material is in side component and outside component there are some strange renders.. when i change material on component/layer it's look like still be there, even if on vray window/skp window material there is not
for example:
i make import green glass on windows, when i change material for clear glass, on render windows are still green..

greetings
sorry for my pure English