removing coroline algea from empty tank

[flyfishingkid]

I just upgraded my tank and want to make my acrylic tank ready to sell.
There is no water in it.
I would like to remove all old coralline algae from the tank without scratching the tank.
There are several scratches on the tank as well.
I think I have someone buying it and they said they would buff it out.
I just wanted to make it look esthetically pleasing as possible to sell

 

[Sethjamto]

If you can fill it with a water and vinegar solution and let it soak for a little bit, it should wipe right off.

 

[ebond009]

I've heard of going at it with credit card and a spray bottle of vinegar solution...never tried but I've read that before.good luck!