Mixed polishing solution

The invention discloses a mixed polishing solution which is prepared by mixing and stirring the following components: 10-30g/L of sodium tetraborate, 8-20g/L of sodium citrate, 1-3g/L of sodium silicate, 8-12g/L of sodium benzoate, 1-5ml/L of OP-10 emulsifying agent and the balance of water, wherein the sodium tetraborate and the sodium citrate are main polishing agents; the sodium silicate and the sodium benzoate are antirusting agents; and the OP-10 emulsifying agent is a degreasing agent. Compared with the prior art, the invention has the advantages that the mixed polishing solution is safe and non-toxic and has no offensive odour; favorable polishing performance is achieved due to taking the sodium tetraborate and the sodium citrate as the main polishing agents, and the surface of a polished valve is silver-white and bright; interprocess rust protection is not needed to be carried out on the polished valve due to taking the sodium silicate and the sodium benzoate as the antirusting agents; and the surface