i always buy all of my hobby stuff in my local hobby shop,but last weekend i by for the first time some model master acryl paint. i ask the the guy if i can use alcool for thinner and cleaning,he said "no"the paint is going to turn into sludge,so he sell me the original testor thinner for acryl but at $15.00 for 4 oz bottle,i think is a little to expensive.my question is: is there any substitute for testor thinner?