Microwave induced plasma optical emission spectrometry (MIP OES) was employed for the first time for the monitoring of total cadmium, chromium, lead, manganese, and nickel in modelling clays for children. The same approach was further used for the first time to evaluate chromium and manganese oral and gastrointestinal bioaccessibility based on the consensus INFOGEST protocol. Operational conditions such as pump speed, nitrogen flow, and viewing position were thoroughly optimized for each element. Further methods based on electrothermal atomic absorption spectrometry were optimized for chromium, cadmium, and lead as monitoring alternatives. Afterwards, the validation of the proposed bioanalytical methods was performed. Also, a chromium speciation analysis was performed, aiming to align with international regulations. Limits of quantification with MIP OES ranged from 0.052 mg kg-1 (nickel) to 0.40 mg kg-1 (cadmium) (fresh weight). Trueness was evaluated using spiked samples, certified reference materials, and a mass-balance study showing acceptable results. Total concentrations complied with national and international toy safety directives. Besides, statistically significant differences (p < 0.05) were observed between different brands and between clay colors for chromium. Mean oral/gastrointestinal bioaccessibility was: 6.0/18.8 % (chromium) and 18.5/52.5 % (manganese). Finally, a risk evaluation was performed to complete the whole study, demonstrating safety for children. The proposed method based on MIP OES proved to be an outstanding sequential analytical strategy for the monitoring of modelling clays, providing simplicity, high sample throughput, and greenness compared to conventional approaches.