Why can I see stains inside my Philips grill? Published on 2021-11-29 If you notice visible stains inside your Philips grill, please read here about it. It is normal to see stains inside your Philips grill over time Over time stains become visible at the inner walls and the inner side of the protection glasses of your grill: do not worry, this is normal. This is not harmful in any way, even as all inner parts get very hot during grilling. It also has no influence on the function of your grill. Please continue cleaning your Philips grill according to the cleaning instructions and you can keep using it without any hygienic or health concerns.