A wide bladed filling knife or caulking blade is the ideal tool here with two or three applications of filler being best sanding between coats.
Best decorators caulk for ceiling cracks.
As for on the flat of a wall or ceiling ha well for a start you can not sand it and to brush it with water is going to make it look even worse.
Remember not to over fill as it will need sanding fill it in layers is best.
In the summer when the crack becomes smaller the caulk should compress and look pretty good.
Best used for filling gaps between skirting boards doorframes or the edges of shelves and the wall.
The best remedy i ve found for these situations is to apply self adhesive scrim tape along the crack and then fill over the top of it with a wide band of all purpose filler.
Generally made of flexible acrylic mastic caulk has a smooth plastic type texture.
When you caulk be sure to use a damp sponge to wipe any and all excess caulk from the ceiling and wall.
Lines of caulk can be prone to cracking if applied in the wrong conditions.
Although there are different kinds of exterior caulk available in the market for different kinds of surfaces and uses here are the ten best exterior caulk that you can choose from.
To get rid of ceiling cracks for good you need to fill them with a flexible material that will stretch when the walls move.
Sand down smooth and paint as for flexible decorators caulk is good if its to be used in corners tops of skirting etc.
You will need to rake out the crack use pollyfiller to re fill.
The best sponge is one used to grout ceramic tile.