Alternatives to Blu-Tack, for poster on painted cement block wall?

I have a wall which is white-painted 'breeze blocks' (AKA cinder blocks, I think?) with no plaster or anything. I'm looking for a way to attach e.g. a poster to it, so that it can be removed at a later date, without leaving any permanent stains or damaging the wall.





I don't have the option of changing the wall in some way, as it doesn't belong to me [rented room]. I've heard that on brick, Blu-Tack is a big mistake, as it's impossible to get off. I'm guessing this applies to breeze blocks too - and I know Blu-Tack can stain or damage paint, as well.





Any ideas? Would Sellotape work, for instance?Alternatives to Blu-Tack, for poster on painted cement block wall?
http://www.absoluteproduct.com/pages/han鈥?/a>





Really good website that has ideas for different options to hang pictures and posters. I suggest the track system. It allows you to put one long track and then you just add the hanging wires onto that track. You can change your posters and pictures without having to put holes in the walls or put up that sticky tack and you can change the height of things so easily. Great system, I saw it on HGTV's ';Don't Sweat It'; and it looked amazing! Good Luck