What is the nature of the sample you are going to analyze: protein, nucleic acids, or small molecules?
If it is protein or nucleic acids, then you can probably leave the RNase in the sample. Also, there would be no need to inhibit the RNase, because once it has consumed all the single-stranded RNA, it will no longer have any substrate and will be essentially inert.
If you are analyzing small molecules, then you can use a small ultrafiltration unit to remove the RNase protein. Alternatively, you could precipitate it with trichloroacetic acid, or with perchloric acid followed by potassium carbonate.