Goliath beetle won't relax?

In my experience, Goliathus specimens take longer to relax than virtually anything else that I've worked with. Other collectors I've spoken with reported the same.

Inject with plain tap water, (hot water unnecessary) the intersection point of legs attached to body 1/2 cc per leg maximum, place back in relaxer for two days. Use chlorocresol in your relaxing chamber and you will never get mold growing, even years later.  I first wrote about this method in 1973.  There weren't any fine gauge hypodermic syringes a half century ago.   You can get disposable insulin syringes at any pharmacy without a prescription.  Get 1cc and up size disposable syringes, WITH 31 gauge needles.  You can reuse the same syringes for years using water.  Some solvents and chemicals will cause the rubber plunger to swell.

With stiff legs, dip a small paint brush in some Gin. Touch each joint of the leg and let the capillary action draw the Gin into the joint. Do each joint a few times, let sit for a few, gently work the joints loose. If not yet moveable, repeat process. I have many Goliath beetles and believe me, it works. This also works w stiff mandibles of Lucaniids etc.