Although there are many different places inside and outside of your home that can be sealed with caulk, the application technique will be essentially the same in most cases. Surface Preparation Making sure that the surface you are going to caulk is clean and well-prepared is essential to achieving good adhesion and a smooth bead. Do not use soap. New caulk will not adhere well to acrylic caulk that has been cured - and will not stick at all to cured silicone caulk. If the surface is mildewed, use a concentrated mildew killer after removing the old caulk.
Caulk has a shelf life of one to two years.
To ensure that your caulk is fresh enough to work properly, test it on a non-porous surface before you begin your project. Make sure that the caulk sticks, comes out of the cartridge smoothly, and most importantly, that it cures in the time it is supposed to. We recommend practicing on newspaper if you are caulking for the first time. The tapered nozzle of the caulk cartridge must be cut before you begin. The further down the nozzle you cut, the larger the opening.