I used to use an old sock which I cut from the heel up. I sleeve it in over the shoe. I worked just fine. I actually used them in both shoes to keep them away from water and street dirt.
I also have used rubber sleeves on the lever and those rubber pads that attach to the shoe, but those cost more than $5.
I also have used rubber sleeves on the lever and those rubber pads that attach to the shoe, but those cost more than $5.