To achieve a beautiful finish with a sponge brush, it's important to invest in a high-quality tool. The quality of sponge brushes can vary significantly, so it's crucial to select a durable brush that can withstand multiple cleanings without deteriorating.

A good sponge brush should also have a high absorption capacity, allowing you to apply varnishes and other finishing products with precision and efficiency. By choosing a sponge brush that meets these criteria, you can achieve a high-quality finish with ease.

It is possible to varnish furniture with a Sponge brush, but it may be more complex than using a traditional synthetic bristle brush. Here are the steps to successfully apply varnish with a sponge brush:

1. Prepare the varnish by mixing it well and pouring it into a clean container. Let it sit for 10 to 15 minutes.
2. Dip the end of the sponge brush into the varnish and wring it out well to remove any excess liquid. You can also remove excess varnish with a paper towel.
3. Apply the varnish using even and regular strokes, avoiding applying a too-thick coat, which could cause bubbles and irregularities.
4. Let the varnish dry according to the manufacturer's instructions, which may take several hours.
5. Apply a second coat of varnish if necessary to achieve the desired appearance.

In summary, varnishing furniture with a sponge brush can be a bit more complicated than with a traditional brush, but by following these steps, good results can be achieved.