I have 5 or so different colors of cut paste that normally works pretty good. My tubes are now several years old and the cut paste has thickened up in the tube and it is difficult to spread the paste on cuts when it is like this. A solution to this problem is to simply place the tube in the microwave and warm it up for about 20 seconds. It reverts back to its more fluid state, just make sure to not burn yourself. I have made a new page for this titled Cut Paste under Bonsai Basics.

Please make sure your tube of cut paste does not have any metal parts to it and if it does do not put in the microwave. You might try running it under hot water instead.