Ps-Clem Hom 11.280:11 :ܕܡܕܟܝܢ ܐܢܬܘܢ ܒܪܗ ܕܟܣܐ ܘܕܙܒܘܪܐ܂ ܘܡܢ ܠܓܘ ܡܠܝܢ ܨܐܘܬܐ‏ : you clean the outside of the cup and plate, while inside they are full of filth
See the entire entry for ṣāˀū, ṣāˀūṯā n.f. uncleanness