We use glucose oxidase blocking.  Works nicely and the sections keep
good morphology.

Our protocol is below if you are interested.

Use 1 unit per ml glucose oxidase in your final buffer,  we make up
stock buffer: 
1 litre PBS
1.8 g glucose
64 mg Na-Azide.

We just heat the buffer to 37 C in a water bath, add the glucose oxidase
for 15 min, remove from the water bath and incubate the slides for 15
min.  Simple.

Phil

"t.hacker@har.mrc.ac.uk" wrote:

> What are you using for blocking endogenous peroxidase in acetone
> fixed frozen sections?
> I have used a weak solution of H202 which is not always effective,
> too strong and I get excessive "bubbling" of the tissue. Yes, I
> know, try a strength in between, but I was wondering if there is
> something more appropriate and less aggressive.
> I look forward to a wealth of knowledge and experience, preferably
> by 9am GMT tomorrow.
> Many thanks,
> Terry.
> Terry Hacker,
> Medical Research Council,
> Harwell,
> Didcot,
> Oxfordshire, OX11 ORD
> 01235 834393 x360