How To Clean a Used Trowel

First, if your trowel is very old or unique, please do not do more than clean the dust off. For all other trowels, read on.

The average used trowel bought for $3 at a flea market will be encrusted with mortar, concrete, tar, or all three. It will need heavy duty cleaning to bring it to usable condition. See the list of supplies below.

Start by protecting the handle with a coat of paste wax, which is easily removed later. Place the trowel on a board or other sturdy outdoor work surface. Flood the blade with water and attack the mortar with the scraper. Work with the grain of the blade, which was ground diagonally parallel with the 2 sides of the tang. This will help minimize scratches in the steel. Continue washing the blade with water as you go.

After removing as much as possible with the scraper, switch to the stone and use it like a sanding block. The grit in the stone is harder than the mortar, and does a good job of abrading it. Take care to concentrate on the mortar, avoid too much wear on the steel. and use lots of water. Use the scraper again where needed, like on the tang.

Turn the trowel over and repeat the cleaning on the bottom. Here the grain runs straight from toe (tip) to heel.

Last, use the 400 grit paper for spot sanding and a final all-over cleaning. Dry the trowel very well. If the handle needs sanding or scraping, wait until the wood is completely dry. Last, protect your work with an all-over coat of paste wax.              

You will need:
Outdoor work space
Paste wax (the yellow stuff in a can)
Carborundum or equivalent rectangular sharpening stone
Steel scraper with a beveled edge (mine is a 1.25 inch Hyde with black nylon handle)
Automotive grade 400 grit sandpaper
Water resistant sanding block
Bucket of water
Shop towels
  

Cleaning this $3 purchase revealed a pre-1955 Disston trowel