brasso

[marton]

Does anyone out there know how to remove the dried on brass cleaning polish that accumulates in the grooves and crevices in brassware?

[weeal]

put some fresh brasso on an old toothbrush and soften it then put a thin cloth over the toothbrush and buff it out

[ianmunt]

warm soapy water

[coccinelle]

I use an accumulation of both weeal and ianmunt's answers; a toothbrush and warm soapy water.