rotary scratches on Aluminium

I've only every milled aluminium with a spray mist/coolant/lubricant.

Yesterday I used a machine that didn't have this and so splashed oil on everything with a paintbrush.

Afterwards noticed that there was a lot of rotary scratching on the faces of the material.

Was that because there was no spray mist?

Or was it for some other reason (it's true the mill had a max rpm of only 3000 but slowed the feed accordingly as per Gwizard).

Not getting very far with this! May I put the question another way?

What factors increase circular scratching when milling Aluminium?

And what can be done about it?

Thanks!

Sounds more like a worn cutter.
Cheers
Roger