Q&A on Quality & Storage
Can I store the residual mix of leftover hair dyeing product?
No. This residual liquid is liable to expand, and storing it is dangerous. The pressure created by gases released by the leftover product may cause the container to explode, so do not store it in a sealed container. If the residual liquid is spattered it may permanently stain the surrounding area. For this reason, be sure to dispose of any leftover product. You cannot dye your hair with this residue anyway.
N.B.: Cream-type products can be saved for future use as long as it has not left the tube.