A company sells chocolates. Demand is recorded weekly. The future demand is estimated using the sales for every week in the previous 3 years. But the sales pattern is corrupted by promotions that have been run by the marketing department from time to time. Typically such promotions last 2 weeks and result in temporary spurts in sales.
The objective is to remove and smooth such spikes that occur (spread over 2 weeks or less).
How could I go about this? Here is a graph
The possible ways I can think of are KDE (Kernel Density Approximation) and LWR . What should be the best approach?