Tried some brass fan jets for a couple of weeks - didn't get on with them, I wasn't happy with the rinsing speed and as a consequence, took longer and used more water.
I know that there are some better plastic fan jets on the market, but I'm happy with pencil jets at the moment.
I think the ones I use are around 2mm - does anyone make a pencil jet thats 1mm or 1.5mm? as surely it would use less water?