Picture 1
Picture 2
Picture 3
Picture 4
Picture 5
Pic 1= the problem, pic 2 = part of the answer, pic 3 = the result, pic 4 = the result after the silly plastic gubbins (the bit that makes it a spot blaster) was removed, Pic 5 = The finished article...
You can use dried sand as a blasting medium, I do not recommend the use of the shed though, far better to fit a seat in there and install electric supply so your lovely wife can watch you at work outside while she is fully protected and making you brews from the safety of being inside... ...