Hi GMC!

Here's a classic Jazz Blues chords progression I used in this lesson :

I Bb7 I Eb7 I Bb7 I Bb7alt I Eb7 I Eb7 I Bb7 I G7alt I C-7 I F7alt I Bb7/G7alt I C-7/F7alt I

So, what scales can we use to improvise over this chords progression?
Of course the Bb pentatonic/blues scale will work fine but we need more options to underline the chords change.

Here are some scale's options I used in the solo:

Bb7 : Bb Mixolydian mode
Eb7 : Eb Mixolydian mode
C-7 / F7 = II / V in Bb : Bb Major scale
Over altered chords we will use the altered scale : that's the seventh mode of the melodic minor scale.
For exemple the G altered scale can be built from Ab melodic minor.
You'll also find here and there some chromaticism and passing tone.