Since the previous tenants of our apartment was a heavy smoker and are in one room wooden panels on the ceiling, the smoke there extremely determined. After the wash with Chlorix and Co. brought only minimal improvement, we had set the last hope in SmokeEx.
We have to sprayed the wood panels generously, allow to dry and repeat the process. With great success - the smell of stale smoke is hardly or no longer perceptible. Even after weeks! However, the price of the bottle is a bit pricey.
