How do I erase items from a image?

[Scallact]

We can take advantage of the facts that 

• flames are lighter than the background
  
• the background is a horizontal gradient
  

So let's go:

With the rectangle select tool, select this small  zone (I added vertical guides to help move the layer later, but that's not mandatory) and copy-paste it as a new layer
   

Apply a gaussian blur filter, configured like below. Important: check "Merge filter"
   

Layer > Scale layer. Scale it only vertically by unchecking the chain icon first:
   

With the move tool, place the layer above the lights:
   

Set the layer to "Darken only" mode:
   

With the eraser tool and a rectangular brush, erase the pixels over the candles bodies (wax only, not the flames):