ATTENTION
Fire is dangerous and can harm you or your property!
Always take the required safety requirements when handling fire!
Be careful when handling chemicals!
Never inhale or ingest the chemicals!
The solutions must be kept out of reach of children!
Never forget alum and borax are chemicals so NEVER use them on things you get in contact a lot!
I'm not responsible for any damage you take!

I'm going to show you how to fireproof important documents and lots of other things, this won't makes things fully fireproof, if you throw them into fire they will burn, but when you hold them under a lighter they will most likely to stop burning when the lighter is removed. For this we will use fire retardants.
Required materials if you use alum(For things you touch less often)
0.1 kg alum(100g)
0.1 liter water(100g)
bowl
Required materials if you use borax (for things your skin get in contact more)
100g borax
2 cups of water
spray bottle
pot
You can find alum in grocery stores,in ebay or in a pharmacy(drug store).
Borax can be found in grocery stores.

Step 1:

What did I make?
I made a fire retardant solution which can protect your important documents, or anything which is close to fire.

How did I make it?
I took a look on the internet for the uses of alum, and I found that it's usuable as a fire retardant, so I tried it out, and it worked.

Where did I make it?
At home, because there is no other place for me to do things like this.

What did I learn?
I learnt that the materials in an old crystaliazation set can be used for lots of things, alum has about 10 different uses from deodorant through fire retardant to astringent(it can stop blood which's coming from a cut).

Step 2: With Alum

If you choose alum then you have to mix the alum with water and stir it until the alum dissolves.
After that put the thing you want to resist fire in the solution and wait five minutes.
Then remove it from the solution and let it hang dry until it becomes tougher. Never use a dryer!
Repeat the process 2-3 times!
That was it, enjoy your fire resistant paper!
Note
First you should experiment with smaller amounts to make sure everything is alright.

Step 3: With Borax

Pour two coups of water into a pot, and put it on the stove.
When it begins to boil you should reduce to medium heat.
Add 100g of borax to the boiling water and stir until it fully dissolves!
Turn the stove off and wait until the water cools down.
Pour it in a spray bottle and spray the thing you would like to become fire retardant!
The image is very bad quality, the water looks slightly clear, but it should be something like the color which you can see in the 2nd image.

Step 4: Finally...

Thanks for reading, I hope it was helpful!
Oh and I'm participating in the indestructibles contest, because it makes things less damageable, so if you liked it then vote for it :).
Sadly I couldn't take a picture (or capture a video) of the paper over the fire because my camera is terrible.