If you keep it or leave it to set, the hair dye may explode. If you used the hair dye that you have to mix with conditioner it shouldn 't explode but you should still throw it away because it won’t be good if you decide to use it again. If you used a bottle of hair dye, the hair dye may heat up and spill out of the bottle. There are some bottles of hair dye that you can keep for an extended period of time. If you buy a hair dye that is already mixed in a bottle and ready to use you should be able to keep it. Check the packaging of your hair dye to see the expiration
If you keep it or leave it to set, the hair dye may explode. If you used the hair dye that you have to mix with conditioner it shouldn 't explode but you should still throw it away because it won’t be good if you decide to use it again. If you used a bottle of hair dye, the hair dye may heat up and spill out of the bottle. There are some bottles of hair dye that you can keep for an extended period of time. If you buy a hair dye that is already mixed in a bottle and ready to use you should be able to keep it. Check the packaging of your hair dye to see the expiration