On the spot web comic Boil and bubble

Source: © Jane Webster / Debut Art Ltd.

Answer from Charles Harrison:

The bottle needs to be cooled down as soon as possible. Bulking up waste can be extremely hazardous if incompatible chemicals such as acid chlorides and amines are mixed together. If left uncontrolled, this could become a runaway reaction that could cause a fire or explosion. If the bottle is very hot, it may be advisable to evacuate and call for additional help.

Charles Harrison is a safety adviser at a UK university