Soda crystals are reputed to be good at dissolving grease. They can be used to help clean out a gunged up washing machine, or more importantly to help prevent a build up of grease).
Can soda crystals damage the washing machine drum?
The last time I used some I noticed that on the back of the packet they say that it should not be used on aluminium. I instantly thought about the alloy drum spiders inside washing machines and wondered whether soda crystals could cause any damage.
So I sent an e-mail to a manufacturer of soda crystals. They told me that there shouldn’t be anything to worry about. The only reason they advise against using the soda crystals on aluminium is that it can cause pitting (small indentations). This would be undesirable on anything on show. But as no one can see the drum spider it shouldn’t be a problem. I don’t think the soda crystals would undermine the strength or stability of something made of aluminium, just maybe cause small pitting.