The holes help to teach odor recognition and precise sourcing. We prefer thick, double walled cardboard boxes so they last longer, which make it worthwhile at large competitions such as Sniff Alberta’s nosework trials (when boxes no longer have circular holes drilled in them to assist the dogs). Note that cardboard boxes are safer than wood and metal boxes, since a dog that gets his head stuck can be released by human hands alone, without having to find tools and/or a welder to rescue the dogs.
Hunter’s Heart sells blotting paper pieces pre-scented with cocktail of Birch, Anise, Clove, Wintergreen at: http://store.huntersheart.com/Birch_Anise_Clove_Cocktail_100_blotting_paper_p/bcac100.htm. To do it yourself, shop for blotting paper at art supply stores such as: http://kensingtonartsupply.com/kas/contact-kensington-art-supply/ in Calgary. Cutips make great hides, but have less surface area for cocktailing multiple odors.
Hunter’s Heart sells sliding tins with smooth ventilation holes at: http://store.huntersheart.com/sliding_tin_for_Nose_work_hides_scent_detection_p/tn.htm. Rectangular tins are best because they don’t roll when dropped and these have been used at many classes and nosework competitions. Or do it yourself by purchasing blank tins from http://www.serftosurf.com/. Be sure the surface is smooth, so hands and noses aren’t accidentally hurt by contact.
In practice, focus less on making your hides invisible, and concentrate on securing the hides so your dog can indicate a hide that isn’t rolling or moving, you know for certain where source is located, so you can reward on time without confusion. Judges love to secure tins with glue dots (also available at Shippers Supply), which are also used by banks to attach activation notes to new credit cards. 3M makes a very reliable product, that will secure hides reliably over hundreds of searches, while they take longer to remove than less tacky products such as Frog Tape. Another one of our favourites is small shipping envelopes, which stick well, available at: http://store.huntersheart.com/Sticky_envelopes_for_nose_work_hides_scent_detect_p/pe.htm or Shippers Supply or Uline. Avoid placing them on objects where peeling them off might remove paint and mar the surface of belongings. Some people swear by Quakehold Putty (see http://store.huntersheart.com/Quakehold_Museum_Putty_nose_work_scent_detection_p/qhp.htm), but be forewarned that putty doesn’t work as well at the cold temperatures we experience most often for exterior and vehicle searches.