I saw your comment about protecting the wound spring and introducing acid through the hole. We look at the stored energy as being in the spring as an object. In fact it's actually in the molecular bonds in a form of compression which means the particles are bumping against each other. Even if you glued the spring in place with an acid resistant glue so it cannot unwind, as the molecules chemically react and are freed that higher level of bumping of particles that wants to resolve will be expressed in the chemical reaction. It will result in more heat.
The only reason a spring acts as it does is the bonds that hold the metal together in a particular shape will direct that energy in a certain way. By constraining the spring it will be released into the acid.
