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tokens: reality, some of them may change during a stellar lifetime. Inner processes in stellar evolution such diffusion ( Dotter et al. 2017 ) or planet formation or engulfment ( Meléndez et al. 2009 ; Tucci Maia et al. 2019 ) alter the chemical composition in stars. Other inner mixing processes produced during dredge-up or induced by rotation can alter abundances such as [C/N] or Li ( Masseron et al. 2017 ; Aguilera-Gómez et al. 2018 ). We have to assume today that a selection of chemical abundances remains approximately intact in FGK main-sequence stars and can be used to trace chemical evolution. A few years ago, da Silva et al. (2012) studied several traits for chemical evolution studies of solar-type stars. In particular, [Y/Mg], [Sr/Mg], [Y/Zn], and [Sr/Zn] showed a significant trend as a function of age for their entire sample. When they performed a linear fit of [Y/Mg] as a function of stellar age for a sample of nearby solar twins, Nissen (2015) obtained slope of ∼0.04 dex Gyr −1 and interpreted this relation using nucleosynthesis arguments: massive stars produced Mg and expelled it into the interstellar medium on a different timescale than intermediate-mass stars reaching the AGB and producing Y. This has motivated discussions about whether abundance ratios can be used as “chemical clocks”, in particular if ages are difficult to measure. The exact dependence of [Y/Mg] or [Ba/Mg] on age is still debated, because it seems to further depend on stellar properties such as metallicity ( Feltzing et al. 2017 ; Skúladóttir et al. 2019 ; Delgado Mena et al. 2019 ), but not evolutionary state, at least before the AGB phase ( Slumstrup et al. 2017 ). In addition to [Y/Mg] and [Ba/Mg], [Al/Y] has also shown similar dependences with age ( Nissen 2016 ; Spina et al. 2016 ), at least for solar twins. Several other works that benefit from accurate age estimates have studied trends of abundance ratios as a function of age ( Bedell et al. 2018 ; Spina et al. 2018 ; Delgado Mena et al. 2019 ; Feuillet et al. 2018 , to mention recent works). Most of these analyses have been restricted to using abundance ratios in their classical form, as a function of iron (see Delgado Mena et al. 2019 for exception). Motivated by the fact that the chemical clocks discussed above do not include iron, we searched for other combinations in a sample of 30 elemental abundances. We found 55 relations that are as significant as those mentioned above. This new set of ratios can be used for the same applications as [Y/Mg]. In addition, the ratios can be applied to models of Galaxy evolution and to build stellar phylogenies ( Jofré et al. 2017 ; Jackson et al., in prep.). We report these findings in this Letter. 2. Data and methods We considered the sample of 80 solar twins (including the Sun) that was analysed by Bedell et al. (2018 , and references therein) and Spina et al. (2018) . This is the largest sample of solar twins that has been analysed using the differential technique for