Sims who are young adult or older, and who have at least 6 points in the inventing skill, have the ability to blow up objects for scrap metal by using Detonation Packs. Most objects including cars, furniture, and appliances can be detonated for a small fee (§5 to §65), depending on the size and value of the object. When detonating an object, a Sim throws a timed explosive at the object and runs for cover. After a set period of time, the Detonation Pack explodes, singeing any nearby Sims and destroying or burning any nearby objects, as well as scorching the floor. As a result of the explosion, scrap metal, which can be collected, is scattered around the area. Other objects caught in the blast radius also have a chance of exploding and may start a chain reaction. Therefore, using a Detonation Pack on a large field of small, cheap decorative objects can be an extremely effective way to create a massive explosion. This is a highly efficient method of achieving the Diabolical Detonator challenge as well as any detonation related wishes to blow up X amount of objects.
It should be noted that, although the Sim who is detonating usually runs to a safe distance, this is not always the case. When exploding large junk piles, or if a chain reaction occurs, he or she may get caught up in an unpredictably large explosion and get singed. There are also times when a Detonation Pack will seemingly fail to go off, prompting the Sim to go back to examine it. This rather predictably results in it exploding in their face. The chance of this mishap occurring appears to diminish with increased Inventing skill. Sims cannot die from being caught in a blast, so it is safe to continue blasting and getting blasted even after being singed. Typically, the more it costs to detonate an object, the bigger the explosion will be, with cars and large junk piles typically resulting in the biggest individual explosions. Additionally, the more expensive the item being exploded, the more pieces of scrap metal that will be produced.
Sims who detonate objects on public property outside of the junkyard risk the chance of being fined after a first warning, and of being put on a 7 day notice as a result of further mayhem. While a Sim is on notice, his or her chance of being fined for destruction of public property will increase. Fines will arrive in the form of a bill, therefore, Sims who have the No Bills Ever lifetime Reward can essentially detonate indiscriminately. Having met the Diabolical Detonator challenge will also reduce the chance of getting caught, and will also reduce the price for detonation and result in more scrap metal from explosions. Sims who detonate objects on their own lots will not be fined, however, unlike on a community lot, fires can occur, and there is a chance any Sim caught in the blast will not only be singed, but will be set on fire as well.
Typically, the most practical way to obtain scrap metal via Detonation Packs is by visiting the junkyard and detonating junk piles. However, any cars that drive onto junkyard property are also fair game, and may be exploded without risk of fines -- or, surprisingly, even the fury of the car's owner. Burnt or salvaged objects can also be detonated, but will usually result in only a single piece of scrap metal due to it having no value. This rule also applies to blowing up Fire Trucks, Police Cars, or other objects with zero value.