Use a hoe
Mine sculk blocks with any hoe tier
Avoid using other tools if you want the fastest mining speed
Break sculk blocks by hand only if necessary, but it is slower
Use Silk Touch if you want to collect the sculk block itself
Use Fortune if you want to increase sculk-related drops from sculk blocks
Make sure the area is safe before mining near a Deep Dark or Ancient City
Watch for the Warden and sculk shriekers while mining