Need some plastering advice - pictures attached

[fr0gg0]

Hi all,

I recently moved into a 70s build and need to tidy up some walls. Not sure if it's concrete or mortar in these photos. What would be the best way to tidy this up? Thanks

 

[Eccles]

Had a smilar situation myself a couple of years ago and bought a tub of Wickes Ready Mixed plaster skim which did the job quite cheaply. If you are not used to spreading it on nice and flat, have a little practice first with a flexible plastic taping knife which was what I always use for such jobs. Plasterers would probably say something rude but it's worked for me for years.