How to dissolve composite In2O3 with SnO2 without affecting stainless steel?

I found this [article](http://www.sciencedirect.com/science/article/pii/0022024876902311), but it was not helpful. The $\ce{In2O3}$ is probably amorphous. $\ce{HNO3}$ and $\ce{HCl}$ do not work. Any ideas?




In case your question is about the recovery of indium from ITO, the following might be helpful: 


In *Recovery of indium from indium tin oxide by solvent extraction*, published in *Hydrometallurgy*, **2011**, *107*, 56-61 ([DOI](http://dx.doi.org/10.1016/j.hydromet.2011.01.005)), the abstract seems to suggest that $\ce{H2SO4}$ is more suitable than $\ce{HNO3}$. Furthermore, a solvent extraction scheme for indium, using di-(2-ethylhexyl)phosphoric acid (DEHPA) is proposed.


In *Recovery of indium from used indium–tin oxide (ITO) targets*, published in *Hydrometallurgy*, **2011**, *105*, 207-212 ([DOI](http://dx.doi.org/10.1016/j.hydromet.2010.09.006)), the authors agree on using $\ce{H2SO4}$ (at 90 °C) and decrease the ymount of tin in solution by sulfide precipitation.


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