Getting ready for Sharps Practice:Magenetic Bases

I was looking for a basing solution that would work well with the 1p coins I use for the bases for my Napoleonic figures, and I came across these trays made by Warbases which include small holes for magnets. I bought some rare earth magnets from ebay and spent last night glueing them into the Warbases trays, and applying sand. They work a treat and as you can see are capable of holding figures in place even if the tray is inverted. This figure is a plastic one but the magnets are just as capable of holding a metal figure. The only problem is that some older copper coins in the UK are not magnetic and when I first started basing my Peninsular War armies I never bothered to check if they were magnetic, as a consequence I will now have to re-base all the figures who don't have magnetic coins as bases (doh!).