To remove PU foam from a white-coated aluminum front door, you can try using a solvent such as acetone or nail polish remover. Apply the solvent to a clean cloth and gently rub the affected area until the foam starts to dissolve. Be sure to test the solvent on a small, inconspicuous area of the door first to ensure it does not damage the coating. If the foam is stubborn, you may need to carefully scrape it off with a plastic scraper or putty knife, being careful not to scratch the door. **

Walter White uses aluminum foil on his teeth in Breaking Bad to protect them from the effects of the hydrofluoric acid he uses to dissolve a body in a bathtub. Hydrofluoric acid is highly corrosive and can cause severe burns and tissue damage, so Walter uses the aluminum foil as a makeshift barrier to prevent the acid from coming into contact with his teeth. This demonstrates Walter's resourcefulness and quick thinking in a dangerous situation. **

It is not just your impression, a white surface does indeed reflect more light than the shiny side of aluminum foil. This is because white surfaces reflect all wavelengths of light equally, while shiny surfaces like aluminum foil reflect light at specific angles, causing some light to be absorbed or scattered. The white surface acts as a diffuse reflector, bouncing light in all directions, whereas the shiny side of aluminum foil reflects light in a more directional manner. **

The white line at the top of images from Illustrator is likely due to an issue with anti-aliasing during the export process. Anti-aliasing is a technique used to smooth out jagged edges in images, but sometimes it can create a thin white line at the edges. To avoid this issue, you can try adjusting the anti-aliasing settings or manually cropping the image to remove the white line. **

To change the entire background back to white in Adobe Illustrator, you can simply select the artboard by clicking on it. Then, go to the "File" menu, choose "Document Setup," and select "Edit Artboards." In the Artboard Options window, you can change the color of the artboard to white by selecting it from the "Color" dropdown menu. Click "OK" to apply the changes and the entire background will be changed to white. **

If Illustrator is displaying everything in black and white, it may be due to a few different reasons. First, check to make sure that your document color mode is set to RGB or CMYK, rather than grayscale. You can do this by going to File > Document Color Mode. Additionally, check that your individual objects and layers are not set to grayscale color mode. You can check this by selecting an object and looking at the color swatch in the toolbar. Finally, make sure that your display settings on your computer are not set to grayscale. You can adjust this in your computer's display settings. **

To remove the white milky film that has formed on the new windows after removing the aluminum foil used as heat protection, you can try using a mixture of water and white vinegar. Simply mix equal parts of water and white vinegar in a spray bottle, then spray the solution onto the affected areas of the windows. Use a clean microfiber cloth to wipe the windows in a circular motion until the film is removed. If the film persists, you can also try using a commercial glass cleaner or a solution of water and mild dish soap. **

If there are black spots on a white designer t-shirt, it is important to act quickly to prevent the stains from setting in. First, gently blot the area with a clean cloth to remove any excess dirt or debris. Then, pre-treat the stain with a stain remover or a mixture of water and white vinegar. Wash the t-shirt in cold water with a mild detergent, and avoid using bleach as it can damage the fabric. Finally, air dry the t-shirt to ensure the stain is completely removed before wearing it again. **