If you've got a 0.5mm or larger nozzle, a good thing to use when changing between ABS and PLA is Laywoo-D3 wood particle filament. I wouldn't try Laywoo-D3 in anything smaller than 0.5mm though - tends to clog.
It will run at both ABS and PLA temps, so you simply leave your extruder at the temp you were using, push the Laywoo-D3 through (to remove all your old plastic, then as soon as you get clean wood extrusion, change the temp to what you want to use and repeat the process with the new plastic you want to use.
Note: If you can, when changing you should probably back out most of your filament while slightly colder (eg: PLA reversed/pulled out at say 160 if you use 185, or ABS reversed/pulled out at say 190 if you use 225) to remove most of the existing filament, and hopefully not waste as much. You still run the Laywoo-D3 through at the normal temp.
FWIW: I tend to just remove the idler pressure from my extruder drive (so I can pull/push by hand), turn off the hot end, then watch the temp drop. Once it hits the target withdraw temp for that plastic, I just pull it out by hand. I can them just turn on the extruder again and feed through the Laywoo-D3. Rinse and repeat with the target plastic once you've got the Laywoo-D3 done and you're switched.
It will run at both ABS and PLA temps, so you simply leave your extruder at the temp you were using, push the Laywoo-D3 through (to remove all your old plastic, then as soon as you get clean wood extrusion, change the temp to what you want to use and repeat the process with the new plastic you want to use.
Note: If you can, when changing you should probably back out most of your filament while slightly colder (eg: PLA reversed/pulled out at say 160 if you use 185, or ABS reversed/pulled out at say 190 if you use 225) to remove most of the existing filament, and hopefully not waste as much. You still run the Laywoo-D3 through at the normal temp.
FWIW: I tend to just remove the idler pressure from my extruder drive (so I can pull/push by hand), turn off the hot end, then watch the temp drop. Once it hits the target withdraw temp for that plastic, I just pull it out by hand. I can them just turn on the extruder again and feed through the Laywoo-D3. Rinse and repeat with the target plastic once you've got the Laywoo-D3 done and you're switched.