Your hands are a good source of RNase, avoid touching any of the slides or slide boats with bare hands throughout all steps. Use slide boats and dishes that are designated for in situs .
Acid clean the slides.
Be sure to rinse in tap water and running distilled water. Avoid any contamination with general labware. Add 5g of gelatin while mixing the water with a stir bar. Avoid creating bubbles when dipping the slides in the subbing solution. Cover and let dry overnight.