How to make fake airfilled cans
 
Why fake airfilled cans?
There are collectors that collect full cans, because they like the can unopened.  It is possible that after a couple of years these cans go leaking the fluid that is inside. So to keep the can intact, you can make a fake airfilled can.
 
How to make airfilled cans?
The nicest way to make a fake airfilled can, is by hiding the little hole as good as possible
Here is the way I use (only when the can is past the expery date):

Step 1: The beginning

When you get the can it looks like this 

Step 2: The turning

Turn the tab pull as shown in the picture 
(that's 180 degrees)
 

Step 3: Making the hole

Take a needle or a pin (or another small sharp object) 
to make a little hole as shown

Step 4: emptying the can

(This step is done in the bathroom, toilet or outside)
Shake the can well. turn it upside down and take out the needle or pin. Now the fluid will
escape from the can. Leave the can for 5 minutes upside down to let all the fluid escape.
if there is still fluid in the can and it will not come out, put both your hands around the can
(still upside down) and hold it like this till all fluid has escaped.

Step 5: The little hole

When your done, you will see a very little hole 
 

Step 6: The final step

After you have dried the can, just turn back the tab 
to it's original place. You now have a fake airfilled can
with a difficult to detect hole.
 

How to recognize fake airfilled cans?

Cans made by this method can be sold as real airfilled cans. There is a difference between
real airfilled cans and fake airfilled cans. The difference is that real airfilled cans do not have
a hole out of which the fluid has escaped. There are two ways to check if a can is really air-
filled or is a fake

method 1: The easy way
When you turn the pull tab 180 degrees and look for a little hole. if no hole is found use method 2.

Method 2: The hard way
Put the can in hot (around 50 degrees celsius) water. if you see air escaping the can, you know the can is not really airfilled.  You can also cool the can in the fridge first, This way the effect will be better.