This is Qiagen's Tissue Lyser, the best tool to homogenize 24 or more tissue samples in Trizol in one single shot. Without cross-contamination. It has been three years that I don't touch a Polytron, and my life it's much easier.
Basically, at the time of tissue dissection, I'm taking a piece of tissue, putting it into a 2 mL eppendorf tube, adding a 5 mm inox bead and flash freezing in liquid nitrogen. The day of RNA extraction, I put my tubes in ice, I add 1 mL Trizol and I directly thaw/homogenize in Tissue Lyser for 2-5 minutes depending of the consistency of the tissue. The bead follows the Trizol protocol without interference, so I can also centrifuge the tube with the homogenate + bead for phase separation after chloroform addition. There are no Polytron probes to clean and the beads can be trashed away or reutilized if you prefer so.
I'm also using the same approach but for enzymatic assays in tissue lysates (of course, by replacing Trizol with appropriate assay buffer).
I'm writing this words as a spontaneous non-sponsored expression of love. I love Tissuelyser! What I don't love is the price of the stupid inox beads, but I found a cheap solution for it.