The water-miscible cyclic ethers tetrahydrofuran (THF) or 1,4-dioxane can be considered, aiming at selectively dissolve the residual polycaprolactone (PCL) blocking the poly(methyl methacrylate) (PMMA) microchannels. They can be mixed with aqueous solution of sodium or potassium hydroxide to promote alkaline hydrolysis of the PCL ester bonds, and hence depolymerisation.

Still another option to be considered might be aqueous acetonitrile solution; cf. G. L. Siparsky, K. J. Voorhees, F. Miao, "Hydrolysis of polylactic acid (PLA) and polycaprolactone (PCL) in aqueous acetonitrile solutions: Autocatalysis", J. Environ. Polym. Degrad., 6(1) 1998, pp. 31-41; http://link.springer.com/article/10.1023%2FA%3A1022826528673

A few solvents suitable for PMMA were listed elsewhere at this forum: https://www.researchgate.net/post/With_PMMA_which_solvent_to_use