Examples of sources rejected in the third step of our cleaning procedure. Left: BIz colour cut-outs of a narrow-band selected LAE (ID_CANDELS=23527, z = 3.116). The green circle has a radius equal to the NB3727 PSF full width at half maximum. The stamp covers about 4′′ × 4.5′′. See Appendix A for the details on each clump. Right: object ID_ECDFS=42881 (z = 3.16). It is found in the GEMS catalogue. From the left V, z, and V−z, stamps taken from GEMS images. The stamps cover an area of about 2′′ × 1.5′′. The red contours represent levels equal to 4,7, and 10 times the value of background. This AGN is excluded from our sample because a source lies on top of it.