Your doc is right on some oxidation issues, but proper storage of pre-cut or 
pre-bought slides can solve this. I have done intensive studies for 
oxidation, in my own lab(never published) and have found when stored in 
freezer, regular household one,
antigenicity can be held for up to 6 mos, also sealing of blocks is more work 
than necessary, when you trim and toss first couple of sections, tissue  is 
fresh and new, so antigenicity is ok, heating and re-blocking can be more of 
an issue than re-cutting. I could go on and on. If you need additional info 
call me.
                                              dana Dittus
                                              215-481-2609