A few years ago, I created an electrum wallet on a desktop machine with version 1.8.1.

For reasons I won't go into here, I am now limited to the android client for the foreseeable future (and beyond).

I need to sign a message (not a transaction) with the private key associated with a specific bitcoin address in that wallet.

Two questions:

1. Is there any way of doing that?

2. If not, how do I export the private key into another wallet client, so I can sign a message with it?

I can miss the obvious sometimes, but I didn't see any way of doing either of these things.