Although vinegar is great for killing mold, it is not a guarantee. Vinegar can only kill about 80% of known mold species. In order to determine if your mold type can be killed, and if it is non toxic, a professional mold test is required.
On the plus side, vinegar, unlike other household products like bleach, does not give off harmful off gases and is generally safe to use. It is still recommended to wear protective gloves and eye wear when using vinegar to kill mold as vinegar is an acidic product.
Start by using distilled white vinegar that is mixed with water.
Spray the vinegar solution directly onto the moldy surface and leave it to sit for at least one hour so that the vinegar can saturate the mold. DO NOT spray the vinegar solution onto a cloth or sponge and wipe the mold. This will only send spores airborne allowing them to rest elsewhere in your home.
After the solution has sat for an appropriate amount of time, wipe the moldy surface clean with water. The surface should then be allowed to dry.
To get rid of the smell of vinegar, keep a window or door cracked to allow fresh air in.
Repeat this process every few days to prevent any mold spores from growing and reproducing.
Disclaimer: Mold is a very serious and can be very damaging to your health. Unless you are certain that the type of mold you are dealing with is non toxic, you should never attempt to remove it yourself. A certified mold inspector can tell you the type of mold you have.