How to reach very tall ceilings in a staircase?

I use my pool brush!

Rent ladders and scaffolding from any tool rental shop. Rent extra long paint poles too. Just be very careful. Or, hire out the stairwell portion of the project to a local painter and electrician.

Absolutely listen to Naomi’s suggestion. BUT, before planning to do it yourself, go to Thumbtack.com or Angieslist.com or HomeAdvisor.com, or similar sites. Get estimates from accredited professionals and then weigh what your time (and possible injury) is worth. Negotiate cost by offering yourself as a helper, so next time you’ll know. Just a thought from an old lady.

Rent scaffolding from a reputable equipment rental place, and have them set it up.

Often it is actually more cost effective to have a professional do the work. They have the appropriate tools and accessories and experience. Nearly any type of project involving scaffolding, etc. will take the novice longer to do than if you have all the changes chosen and then have the pro's do the actual work.

Thanks all, I actually found a way to do it on YouTube once you all suggested scaffolding!