[Histonet] alk phos, again

[Emerson, Rachael]

Other there other methods to block endogenous alkaline phosphatase?
I am using mouse embryos, frozen sectioned. I've tried:

levamisole at varying concentrations:  still background
heated PBS at varying times:  too strong, blocked my signal
15% acetic acid at 15":  too strong, blocked my signal
5% acetic acid at 15":  still background
usually I did a combo of levamisole and another treatment.

I appreciate any thoughts.......
Thanks!
 Rachael