Blu Tack, the original re-usable Adhesive - Standard pack

Blu Tack is a permanently plastic, reusable adhesive supplied in the form of rectangular slabs between sheets of release paper. Packed in individual wallets, Blu Tack is both clean and economical in use

It has so many uses including masking off camo, such as masking off the teeth of a tread, to masking off pieces from mufflers and exhausts to wheels for painting, the uses are almost endless. 

Please note, if the paint on which you put the Blu-Tack for masking is not fully cured it may discolour the paint!  If that has happened the first gloss coat for decals wil even everything out and it will be invisible.  The best way to get those little sticky bits off when masking is removed is with a ball of the same stuff. Just knead is a second or 2 to get some "fresh" stuff and press it on the stuck stuff a few times and it is gone.