Composition for protection of glassware in dishwasher

1. A method for protecting glassware from corrosion in an automatic dishwashing process comprising providing a composition comprising zinc and bismuth into a dishwasher and washing the glassware in the presence of said composition, wherein the mass ratio of zinc to bismuth in the composition is 1:100 to 100:1, wherein the corrosion is caused by exposure of the glassware to aluminum.

2. The method according to claim 1 wherein the ratio of zinc to bismuth in the composition (by mass) is from 1:10 to 10:1.

3. The method according to claim 1 wherein the amount of zinc and bismuth provided to a dishwasher cycle is from 1 to 1000 mg.

4. The method according to claim 3 wherein the amount of zinc and bismuth provided to a dishwasher cycle is from 5 to 500 mg.

5. The method according to claim 1 wherein the composition comprises a soluble ceramic/glass formulation.

6. The method according to claim 1 wherein the composition comprises a detergent formulation.

7. The method according to claim 1 wherein the zinc or bismuth are in metallic form.

8. The method according to claim 7 wherein the metallic form is an alloy of zinc and bismuth.

9. The method according to claim 1 wherein the zinc and/or bismuth are present as a salt or compound.

10. The method according to claim 9 salt or compound is a nitrate, oxide, sulphate, phosphate, halide, carbonate or carboxylate salt.

11. The method according to claim 9 wherein the zinc is present as zinc acetate, the bismuth is present as bismuth citrate.

12. The method according to claim 1 wherein the amount of silicate is present in a ratio to zinc and bismuth of up to 100:1.

13. The method according to claim 1 wherein the composition further comprises silicate.

14. The method according to claim 13 wherein the silicate is present as a salt.

15. The method according to claim 14 wherein the silicate is present as sodium disilicate.