system
Given the following post, respond as if you're commenting on Reddit:
human
My five year old asked me what if anything can destroy a black hole? help?

Edit - Wow...this blew up!!! My kid is gonna freak out...he honestly is gonna love this, he is constantly asking about asteroids, exploding suns, etc.  We were pretending that I had spaceships and that he had suns which always destroyed my rockets, but then I pulled the trump black hole card and destroyed his sun.  He didn't like that which prompted the question.  Thanks Reddit...what fun!!! Wow...I am not smart enough to read most of what's here.  I'm a lighting designer by trade but seriously you guys are smart.   I'm gonna need about 10 more cups of tea and a weekend to read through the comments. 

2nd Edit - First time front page!! So cool....made my day and my kids day...... :-)
gpt
Nothing external can destroy a black hole.  However, a black hole will eventually disappear on its own (but eventually here means an absurdly long time).

A black hole has a boundary called its event horizon.  General relativity tells us that anything that crosses the event horizon can never get back out, so black holes only grow, never get smaller.

However, there is an effect due to quantum mechanics and discovered by Hawking that causes a black hole to evaporate -- the mass of the black hole turns into radiation that goes away from the black hole.

But note that this evaporation effect is very, very, very slow.  A black hole with the mass of the Sun (which would be a small black hole, only about 3 km or 2 miles in size) would take 10^(67) years to evaporate.  Thus even though black holes will eventually evaporate, the length of time is extraordinarily long (the universe today has been around for only about 14 billion years).