This paper presents abundances for 12 red giants of the old open cluster Collinder 261 based on spectra from VLT/UVES .
Abundances were derived for Na , Mg , Si , Ca , Mn , Fe , Ni , Zr and Ba .
We find the cluster has a solar-level metallicity of [ Fe/H ] = -0.03 dex .
However most \alpha and s-process elements were found to be enhanced .
The star-to-star scatter was consistent with the expected measurement uncertainty for all elements .
The observed rms scatter is as follows : Na = 0.07 , Mg = 0.05 , Si = 0.06 , Ca = 0.05 , Mn = 0.03 , Fe = 0.02 , Ni = 0.04 , Zr = 0.12 , and Ba = 0.03 dex .
The intrinsic scatter was estimated to be less than 0.05 dex .
Such high levels of homogeneity indicate that chemical information remains preserved in this old open cluster .

We use the chemical homogeneity we have now established in Cr 261 , Hyades and the HR1614 moving group to examine the uniqueness of the individual cluster abundance patterns , ie .
chemical signatures .
We demonstrate that the three studied clusters have unique chemical signatures , and discuss how other such signatures may be searched for in the future .
Our findings support the prospect of chemically tagging disk stars to common formation sites in order to unravel the dissipative history of the Galactic disk .