you can try gaffer tape.. (dunno can google).. but its not a 100% solution.. plus after awhile the tape usually comes off...
just take care of where you put, how you carry.. especially if you sling and walk around don't bang into doors or lamp posts...
when keep in bag, try to keep ur lens & camera away from other items such as keys etc... then reduce the chances of scratching them lor..
other than that, if you're a careful user shouldn't be getting any scratches.. unless due to accidents..
For lenses that are small in size, try to use gaffer tape to take 'em. However, to tape the lens properly using gaffer tape requires some skills, otherwise you'll end up having it taped in a ugly fashion.
For lenses that are bulky in size, you can consider LensCoat for an easier alternative but at a higher cost.
personally, i used 2 - 3 layers of mcnett camo form for one of my lens since it's an out of production lens from the 1980s and the most parts of the lens are metal, including the hood
1 layer for my kit lens
For those sitting on the fence regarding using UV filters as lens protection:
Happened this morning....D40 with 35mm f1.8 lens sitting on my desk after cleaning, swiveled my desk chair to get up, and it caught the D40 strap, sending it down to the floor lens pointed down. Fell 30" onto the plastic chair pad over carpet, lens cap flew off, and the filter took the brunt of the impact.
Camera and 35mm lens OK, but the UV did not survive. I going to attempt to post my first pic on this site, but to describe the aftermath.....UV glass shattered, and the threaded portion of the brass ring partially separated from the exterior ring due to the impact. This is B&W's Pro thick brass exterior ring UV/haze 52mm filter, falling only 30".
I will stay with filters with exceptional glass protecting my lenses.