If you’ve ever had a broken filter become stuck on your lens, a wave of anger and relief likely came over you. While the filter may have saved your lens from serious damage, it can be worrisome when trying to remove it. Often times the filter gets stuck on and/or there are sharp glass shards; the obvious concern is the high possibility to cause damage where you just avoided it. Depending on the extent of the damage, there are several ways to remove a broken filter safely.
The first technique is to simply try to thread the filter off with your hand. Be careful where you hold the lens. To prevent damage to the internal barrels or rollers, hold the lens on the same barrel as the filter. Some lenses don’t have much surface area and to make matters worse it’s smooth plastic. A piece of rubber will help you to get a better grip. Sometimes getting a little rubbing alcohol into the threading may help to loosen and lubricate the threads; this is done by applying it to the seam where the filter meets the lens. A variation of this method is to place the lens filter down on a piece of rubber (like a bike tube) with a hard flat surface under it, push down firmly while gripping the same barrel as the filter, and turn. If you are a tool guy or gal, a jar opener (the hand held type) can sometimes help, too.
When you are up against a slanted filter and you need it back on the threads, you can use a small screw driver to pop it in (preferably flathead). Use extreme caution because this method may cause damage to the front barrel. Place the head of the screwdriver into the gap, move around the lens while gently tapping the tip against the seam. The objective is to separate them until the whole seam is even. Some filters will pop right off.
When the filter is broken, it can be removed by using a pair of pliers; lineman’s pliers are best. This method should not be used for lenses with plastic filter rings due to the high probability of damage it will cause. First it is best to remove as much glass shards and particles as possible. Simply grip the filter firmly where the glass is gone, twist inward bending the filter towards the center, and it should come right out. Bolt cutters can be used, but will usually damage the filter ring if not done very carefully.
Most of these methods will only work on minor damage. Despite your best efforts, the filter threads may be damaged. A small screwdriver can sometimes clean up the threads, but replacement may be necessary. In cases where there was physical trauma, often the damage to the filter ring will render it impossible to put filters back on the lens and the filter ring will need replacement; this is most common with the plastic type. Also, if you have any glass remnants use a soft dry brush to clean them out, you do not want to drag shards across your front element. If you take nothing else from this article, remember this: when you try to remove a stuck on filter, be patient and especially mindful where you hold the lens.
*These tips are from a professional repair technician with years of experience in the industry.