To get rid of any scratches on your pram firstly you can check if the marks are actually scratches/indentations into the aluminium frame, or whether it is a surface mark.

If the scratch is only a surface mark, this can be cleaned off with an industrial alcohol-based cleaning wipe.

However, if  the scratch is a indentation into the aluminium, it can be touched up with car touch-up paint that can be purchase from an auto shop.