You will need
  • -solvent;
  • -vinegar or mineral alcohol;
  • knife;
  • -alkali;
  • professionals
The easiest way is to use special solvent to clean off surfaces like building materials. The only thing you need to consider when working with this tool, it removed the layer of sealant. If it is thin, then depart easily after a little processing. If the layer is thick enough, you must apply the product in the quantity specified on the label and leave for a while. As a result, old silicone sealant will simply collapse and you can easily remove it from the surface.
Also you can remove the old layer of sealant with an ordinary knife. The main thing that the knife was comfortable to hold in hand (he must have a small neat handle and the blade). Start removing the old material. Proceed very carefully to avoid scratching the original surface. As soon as I otkrivate all sealant, degrease the surface. Especially if you are going to immediately apply a new layer of glue.
Try to clean the excess sealant as soon as he came to the surface. This should be done fast enough until it froze. And besides, if you immediately engaged in the removal of glue, you can cope only with a damp cloth. And not even a trace will remain.
In some cases (it depends on the brand of glue) you can try to remove silicone sealant by means of ordinary vinegar. However, this is only valid with the materials in which the vinegar is one of the main components. Also apply mineral spirits. Therefore, before starting work, be sure to read the label (if it remains) from the glue, which will be written composition.
Sometimes the hardened sealant cope with alkaline materials. You can buy them, for example in DIY stores. Only work with this cleaner very carefully. Be sure to wear rubber gloves, special glasses for eye protection and apron.
If you yourself can not cope with cleaning the old sealant, you can call professionals. They will help you. However, it will cost you a certain amount. But the result exactly guaranteed.