General recommendations to avoid RNase contamination

From fermentas

    Maintain a separate area, dedicated pipettors and reagents when working with RNA.
    Wear gloves when handling RNA and reagents to avoid contact with skin, which is a source of RNases. Change gloves frequently.
    Use sterile, RNase-free plastic tubes.
    Treat water and all solutions used for RNA purification and handling with DEPC. Add DEPC to 0.1% (v/v) final concentration; incubate overnight at room temperature and autoclave.
    High quality reagents must be used for buffer solutions. Buffers containing Tris should be prepared by dissolving Tris base in DEPC-treated water. Solutions containing DTT or nucleotides should be prepared using DEPC-treated water and be passed through a 0.2 µm filter for sterilization.
    Keep all kit components sealed when not in use and all tubes tightly closed during the transcription reaction.