How do I clean brass really quickly?

Yes, smear on a thick layer of ketchup. Let it sit for a few hours, then wash off with a sponge, repeat where necessary.

Thanks I’ll try that.

we use lemons & salt - same principle as ketchup - but works best when lemons are past their prime - I think the juice is more concentrated when they are dried up some - pour salt onto lemon half, then rub salted lemon onto brass (or copper) - then wash off - I use a little detergent with running water to rinse - BE sure to get all the stray salt washed off afterwards or it pits the metal! & if there is a felt pad on bottom, avoid getting that wet & be sure felt is dried before setting polished item back on a wood surface

I use a dab of white toothpaste on a damp cloth and a dab of toothpaste on a damp toothbrush.

Thank you so much everyone. Have tried the ketchup but it seemed to leave tiny pits . Left on for three hours was that too long? Will try the toothpaste and lemon now.