I am looking to degloss the semigloss paint inside an apartment. I would prefer to use substitute tsp to do this, since it would clean the paint same time as it was deglossing. But I am concerned substitute TSP products don't have the same deglossing properties as real tsp.
Otherwise I'm thinking of using those sanding sponges. Also I heard XIM UMA and other primers are good over semi gloss surfaces, but isn't that an expensive way to deal with the problem?