The extent of yellowing upon aging of bleached material depends on the thoroughness of the original bleaching regime. A final wash in a 2 per cent solution of barium hydroxide, calcium hydroxide, sodium bicarbonate or aluminium sulphate prevents yellowing. Sulphur dioxide can also conveniently be applied as a gas. If allowed to dry, the cellulose plant skeleton that is left after bleaching will become very brittle. Water has a plasticising effect, so a humectant is usually added in the final stages to attract water.
Calcium chloride attracts water well, sodium chloride slightly less so.
Glycerine has also been used. Glycerine and bleach will explode on contact.