UKH

What is the opinion on leaving ticks on a classic sport climb? Say someone is multiple day work a route but not everyday, should they brush after each seesion? or is it OK to leave tick marks and just brush the holds? 

Whether it is classic, or not, tick marks detract from someone trying to onsight. That's said, I often forget to brush so any I make are subtle and small so they will wash off easily if the route gets the slightest rain.

Remove all chalk. Then camouflage the bolts to preserve the adventurous nature of the challenge.

Why stop with tick marks? If you’re going to cheat you may as well go the whole hog and paint the holds in bright colours.

Or just screw big resin jugs into the wall where the old holds were.

Maybe better would be to get an exactly matching hangar (and just the head of a bolt) and attach this fake to the rock with some double sided tape between the fourth and fifth bolts of the route (higher than any clip stick could clip).

The next person to climb it will clip the fake - which will just fall off. They will be very "surprised" and confused and immediately doubt all bolts above and below them. They'll have no idea what's going on or who tampered with what. This will return the adventure but be perfectly safe.

Yes.

Leave as pristine as you can.

Could you just use a little bit of finger tape rather than a chalk mark? Easy to remove and saves continuously plastering the rock with chalk that will eventually leave a conspicuous mark no matter how well you try to clean it.

Then you end up with little bits of tape all over the crag, and tape doesn't wash off. If you're done for the day and taking your drawers home, brush off any chalk. 

I wasn't suggesting that the tape should be left on the crag or that they should litter it around the crag after removing it.

My point was that brushing and a bit of rain doesn't really remove excess chalk, the areas which are repeatedly chalked and brushed will be easier visible if as much for the cleaning as for the chalking.

The e been watching too many videos and think it’s ok but they generally aren’t very bright and should stay on a climbing wall; I see it all the time and lot of climbing groups and companies do it; I have seen tick marks on huge holds in places where it is completely unnecessary