Client termination communication method

I am getting ready to do my first large scale client termination as I need to get rid of the bad, low quality, and low fees type of clients. I plan on sending out 25-30 letters. These are all once a year engagements (tax prep) and none of them are aware this is coming. My normal method of communication is email so I think this the best course. The alternative is snail mail with just a stamp (sending certified seems like too much postage).

How do others normally handle this?

+1 for email. (Better yet, if it comes from a CRM that tracks 'Opens'.)

I understand that email gives you confirmation they opened or received the message but I send snail mail letters each year. Granted they may ignore them but I feel that if I email them it makes it very easy for them to email back about why or “please keep me”! thus creating more back-and-forth between us and wasting my time.

Email if there's no contention and everything is relatively amiable.

Email plus letter sent certified if there's contention and the client might create issues.

When I fired a client last year I did it first class mail and certified. First class meant they got it timely and certified meant that I know they got it.

Overkill? Maybe, but it gave me peace of mind.

I use regular snail mail for this. This hopefully avoids the former client saying they never got the email.