WARNING High voltage electricity can cause death and serious injury.I do not recommend that anyone work with high voltage power sources unless they know how to do it safely.
Step 1: Getting the Materials
1.A long screw
2.Some tin foil
3.A 2L bottle
4.some salt and hot water
The first thing you do is get the cap and put a big screw in it.
Step 2: Tin Foil Time
Now take 15inches of tin foil and fold it in half :)
Step 3: Almost Done!
Step 4: That Wasnt So Hard Was It? :)
Fill the bottle with water and over saturate it with salt,baking soda
(Right now I'm trying water and vinegar 50/50 mix)
These capacitors work great in small Tesla coils and they make a very loud noise
Have fun and be safe