So you got a small hole to fill or maybe a gaping chasm, lets have a look at what is available in Thailand.
Now I have never seen the old polyfilla here and have no idea why, that was great stuff that would botch any job, old rotten window frames or anything, so what we got here in Thailand, we got plaster, grout, white cement, ordinary cement, and bosny wall putty, so lets start with bosny wall putty.
Now this comes ready mixed with a little plastic spreader, great for outside work as it sets off like cement so no future problems, this does have a few bad points though, anything over 5mm deep and you will get sagging before it sets off, so you got to sand down again and re apply to fill the low points, takes a real long time to set in Thailand, I mean hours upon hours, really isn't that easy to sand, but at 40baht per tub it is cheap.